Definir Conjugation in Spanish
The Spanish verb definir means to define, and it is a verb you will use again and again once you know it. Definir means to define, and it is used for giving the meaning of a word, defining a problem, and defining a style: definir una palabra, definir el problema. It is a regular -ir verb, common in school, science and work. Like every Spanish verb, definir changes its ending for each person and tense, and this page gives you the complete picture: every tense, every person, the gerund and the past participle, all from the verified conjugation tables. For example, in the present tense you say defino una palabra difícil, and in the preterite you say definí los objetivos del proyecto. Work through the tables below, read the notes for each tense, and then test yourself with the examples, the common mistakes and the quiz at the end of the page.
Quick facts
- Infinitive: definir
- English: to define
- Verb type: regular -ir verb
- Ending: -ir
- Gerund: definiendo
- Past participle: definido
- Auxiliary verb: haber (all perfect tenses are formed with haber + definido)
Pronunciation is not listed on this page: the verified tables do not include IPA for definir, so no pronunciation is given rather than an invented one. Definir is regular: definí, definía, definiré.
Full conjugation tables
Every form below comes from the verified conjugation tables for definir. The imperfect subjunctive is shown in its -ra forms; the -se forms use the same stem. For reflexive verbs, the pronoun column shows the reflexive pronoun that goes before each form.
Present indicative
| Person | Form |
|---|---|
| yo | defino |
| tú | defines |
| él/ella/Ud. | define |
| nosotros/as | definimos |
| vosotros/as | definís |
| ellos/ellas/Uds. | definen |
Preterite
| Person | Form |
|---|---|
| yo | definí |
| tú | definiste |
| él/ella/Ud. | definió |
| nosotros/as | definimos |
| vosotros/as | definisteis |
| ellos/ellas/Uds. | definieron |
Imperfect
| Person | Form |
|---|---|
| yo | definía |
| tú | definías |
| él/ella/Ud. | definía |
| nosotros/as | definíamos |
| vosotros/as | definíais |
| ellos/ellas/Uds. | definían |
Future
| Person | Form |
|---|---|
| yo | definiré |
| tú | definirás |
| él/ella/Ud. | definirá |
| nosotros/as | definiremos |
| vosotros/as | definiréis |
| ellos/ellas/Uds. | definirán |
Conditional
| Person | Form |
|---|---|
| yo | definiría |
| tú | definirías |
| él/ella/Ud. | definiría |
| nosotros/as | definiríamos |
| vosotros/as | definiríais |
| ellos/ellas/Uds. | definirían |
Present perfect
| Person | Form |
|---|---|
| yo | he definido |
| tú | has definido |
| él/ella/Ud. | ha definido |
| nosotros/as | hemos definido |
| vosotros/as | habéis definido |
| ellos/ellas/Uds. | han definido |
Pluperfect
| Person | Form |
|---|---|
| yo | había definido |
| tú | habías definido |
| él/ella/Ud. | había definido |
| nosotros/as | habíamos definido |
| vosotros/as | habíais definido |
| ellos/ellas/Uds. | habían definido |
Future perfect
| Person | Form |
|---|---|
| yo | habré definido |
| tú | habrás definido |
| él/ella/Ud. | habrá definido |
| nosotros/as | habremos definido |
| vosotros/as | habréis definido |
| ellos/ellas/Uds. | habrán definido |
Conditional perfect
| Person | Form |
|---|---|
| yo | habría definido |
| tú | habrías definido |
| él/ella/Ud. | habría definido |
| nosotros/as | habríamos definido |
| vosotros/as | habríais definido |
| ellos/ellas/Uds. | habrían definido |
Present subjunctive
| Person | Form |
|---|---|
| yo | defina |
| tú | definas |
| él/ella/Ud. | defina |
| nosotros/as | definamos |
| vosotros/as | defináis |
| ellos/ellas/Uds. | definan |
Imperfect subjunctive (-ra)
| Person | Form |
|---|---|
| yo | definiera |
| tú | definieras |
| él/ella/Ud. | definiera |
| nosotros/as | definiéramos |
| vosotros/as | definierais |
| ellos/ellas/Uds. | definieran |
Imperative (affirmative)
| Person | Form |
|---|---|
| tú | define |
| él/ella/Ud. | defina |
| nosotros/as | definamos |
| vosotros/as | definid |
| ellos/ellas/Uds. | definan |
Imperative (negative)
| Person | Form |
|---|---|
| tú | definas |
| él/ella/Ud. | defina |
| nosotros/as | definamos |
| vosotros/as | defináis |
| ellos/ellas/Uds. | definan |
Gerund and past participle
| Form | Spanish | Use |
|---|---|---|
| Gerund | definiendo | with estar for the progressive: estoy definiendo |
| Past participle | definido | with haber for the perfect tenses: he definido |
How to use each tense
Present indicative
Use the present for routines, general facts and what is happening right now. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the present looks like this in a real sentence: Defino una palabra difícil. Learn the present forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Preterite
Use the preterite for finished actions with a clear end, often with ayer, el año pasado or anoche. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the preterite looks like this in a real sentence: Ayer, definí el problema con claridad. Learn the preterite forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperfect
Use the imperfect for background, habits and actions in progress in the past, often with de niño, antes or mientras. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the imperfect looks like this in a real sentence: De niño, definía los objetivos del proyecto. Learn the imperfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Future
Use the future for plans, predictions and promises, often with mañana, el año que viene or pronto. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the future looks like this in a real sentence: Mañana, definiré su estilo en tres palabras. Learn the future forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Conditional
Use the conditional for polite requests, hypotheticals and what would happen, often with si clauses. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the conditional looks like this in a real sentence: Definiría una palabra difícil si pudiera. Learn the conditional forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Present perfect
Use the present perfect for recent actions and experiences, often with hoy, esta semana or ya. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the present perfect looks like this in a real sentence: Hoy, he definido el problema con claridad. Learn the present perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Pluperfect
Use the pluperfect when one past action happened before another past action. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the pluperfect looks like this in a real sentence: Había definido los objetivos del proyecto antes de salir. Learn the pluperfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Future perfect
Use the future perfect for something that will already be finished by a future time. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the future perfect looks like this in a real sentence: Para mañana, habré definido su estilo en tres palabras. Learn the future perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Conditional perfect
Use the conditional perfect for what would have happened under different conditions. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the conditional perfect looks like this in a real sentence: Habría definido una palabra difícil con más tiempo. Learn the conditional perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Present subjunctive
Use the present subjunctive after expressions of wish, doubt, emotion and hope, such as espero que or quiero que. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the present subjunctive looks like this in a real sentence: Espero que él defina el problema con claridad. Learn the present subjunctive forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperfect subjunctive (-ra)
Use the imperfect subjunctive after past wishes and in si clauses about the past, and note the -ra forms shown here; the -se forms use the same stem. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the imperfect subjunctive looks like this in a real sentence: Si él definiera los objetivos del proyecto, todo cambiaría. Learn the imperfect subjunctive forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperative (affirmative)
Use the affirmative imperative for direct commands, instructions and invitations. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the affirmative imperative looks like this in a real sentence: ¡Define su estilo en tres palabras! Learn the affirmative imperative forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Imperative (negative)
Use the negative imperative, always with no, to tell someone not to do something. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For definir, the negative imperative looks like this in a real sentence: No definas una palabra difícil. Learn the negative imperative forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.
Example sentences
Ten natural sentences with definir, covering different tenses and persons. Each one uses a form from the tables above.
- Defino una palabra difícil. — I define a difficult word.
- Define el problema con claridad. — He/she defines the problem clearly.
- Ayer, definí los objetivos del proyecto. — Yesterday, I defined the project's objectives.
- Antes, nosotros definíamos su estilo en tres palabras. — Before, we used to define his style in three words.
- Mañana, tú definirás una palabra difícil. — Tomorrow, you will define a difficult word.
- Yo definiría el problema con claridad si tuviera más tiempo. — I would define the problem clearly if I had more time.
- Él ha definido los objetivos del proyecto. — He has defined the project's objectives.
- Espero que él defina su estilo en tres palabras. — I hope he defines his style in three words.
- Yo ya había definido una palabra difícil antes de salir. — I had already defined a difficult word before leaving.
- Ellos definían el problema con claridad cuando eran jóvenes. — They used to define the problem clearly when they were young.
Common mistakes
- Wrong: Yo define una palabra difícil. — Right: Yo defino una palabra difícil. — The person matters: define is the él/ella/Ud. form, while the yo form is defino. Using the third-person form with yo is one of the most common beginner errors.
- Wrong: Ayer yo defino el problema con claridad. — Right: Ayer yo definí el problema con claridad. — The present and the preterite are different tenses: defino is happening now, while definí is a finished action in the past. Use the preterite with ayer.
- Wrong: Treating definir and explicar as identical in every context. — Right: Definir means to define, while explicar means to explain. — They overlap, but each has uses the other does not: definir fits sentences such as Defino una palabra difícil, while explicar belongs in a different sentence. Check the meaning you want before choosing.
- Wrong: Yo soy definido el problema con claridad. — Right: Yo he definido el problema con claridad. — Spanish perfect tenses use haber, not ser: he definido, has definido, ha definido. Ser plus the participle makes a passive, not a perfect tense.
- Wrong: De niño, yo definí los objetivos del proyecto todos los días. — Right: De niño, yo definía los objetivos del proyecto todos los días. — For a repeated habit in the past, use the imperfect (definía), not the preterite. The preterite (definí) is for one finished action.
Quiz: test yourself
Ten questions on definir. Choose the right form, then check the answer key below.
Complete the sentence: Yo ___ una palabra difícil. (present tense) A. defino B. defines C. define D. definimos
Complete the sentence: Ayer, él ___ el problema con claridad. (preterite) A. definí B. definiste C. definimos D. definió
Complete the sentence: Antes, nosotros ___ los objetivos del proyecto. (imperfect) A. definías B. defino C. definíamos D. definía
Complete the sentence: Mañana, tú ___ su estilo en tres palabras. (future) A. definiremos B. definirás C. definiré D. definirá
Complete the sentence: Yo ___ una palabra difícil si pudiera. (conditional) A. definiría B. definirías C. definiríamos D. defino
Complete the sentence: Espero que él ___ el problema con claridad. (present subjunctive) A. definas B. definamos C. defino D. defina
Complete the sentence: Si yo ___ los objetivos del proyecto, todo cambiaría. (imperfect subjunctive, -ra form) A. definiéramos B. defino C. definiera D. definieras
Complete the sentence: Nosotros ___ su estilo en tres palabras. (present perfect) A. ha definido B. hemos definido C. he definido D. has definido
Complete the command: ¡___ una palabra difícil! (affirmative imperative, tú) A. define B. defina C. definamos D. definid
Which is the gerund of definir, used with estar for the progressive? A. definido B. defino C. definí D. definiendo
Answer key
- defino — The yo present tense of definir is defino.
- definió — The él/ella/Ud. preterite of definir is definió.
- definíamos — The nosotros/as imperfect of definir is definíamos.
- definirás — The tú future of definir is definirás.
- definiría — The yo conditional of definir is definiría.
- defina — The él/ella/Ud. present subjunctive of definir is defina.
- definiera — The yo imperfect subjunctive, -ra form of definir is definiera.
- hemos definido — The nosotros/as present perfect of definir is hemos definido.
- define — The affirmative tú imperative of definir is define.
- definiendo — The gerund of definir is definiendo: estoy definiendo. The participle definido is used with haber instead.
Frequently asked questions
What does definir mean in English?
Definir means to define. It is used in everyday situations such as Defino una palabra difícil. The exact English wording depends on the context, but the core meaning stays the same across the tenses.
Is definir regular or irregular?
Definir is a fully regular -ir verb, so every tense follows the standard endings for its class. Once you know the regular pattern, you can produce every form on this page, including defino in the present and definí in the preterite.
What is the difference between definir and explicar?
Definir means to define, while explicar means to explain. They are easy to confuse because they appear in similar situations, but they are not interchangeable: use definir when you mean to define, as in Defino una palabra difícil, and use explicar for to explain. When in doubt, check the object of the sentence — it usually shows which verb fits.
How do I say “I define” in the past?
It depends on the kind of past. For one finished action, use the preterite: yo definí el problema con claridad. For a repeated habit or background in the past, use the imperfect: yo definía los objetivos del proyecto. For something that has just happened, use the present perfect: yo he definido el problema con claridad.
How do I practise definir?
Start with the present tense table, then drill the preterite and the imperfect, since those two past tenses cause the most mistakes. Try the definir examples and quiz page for more sentences, and use the Spanish Verb Quiz to test the forms under pressure.
Related links
- Definir in the present tense — the full present-tense table for definir.
- Definir examples and quiz — more example sentences and practice for definir.
- Spanish verbs — the Spanish hub, with every verb and tense guide.
- Constituir conjugation — another -ir verb to compare with definir.
- Desistir conjugation — another -ir verb to compare with definir.
- Consentir conjugation — another -ir verb to compare with definir.
- Spanish Verb Conjugator — conjugate any Spanish verb in every tense.
- Spanish Verb Quiz — test yourself on real conjugated forms.