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si

Spanish, conjunction

si is spelled S-I (2 letters) and appears 3,890 times per million words in written Spanish, the 26th most frequent Spanish word form (wordfreq, 2021 data). Si is a Spanish conjunction meaning “if, whether” (English Wiktionary, September 2026). With an accent, sí is a different word: “himself, herself, itself, themself, themselves”. The Spanish Wiktionary (Wikcionario) defines it as “Implica condición o hipotesis”.

What does si mean in English?

conjunction

  1. 1

    if, whether

  2. 2

    points out a contradiction (and often implies that it's obvious or that it's easy to find out about)

    ¿¡(Pero) a dónde va este!? ¡Si la carretera está cerrada!

particle

as sí
  1. 1

    yes, yeah, (used to respond affirmatively to a question, used both informally and formally)

  2. 2

    Used to give positive emphasis to a verb, which is often replaced. Functions similarly to English do.

interjection

as sí
  1. 1

    Spainhello? (used when answering a phone call)

noun

as sí
  1. 1

    masculineyes; aye, ay; approbation, acceptance

pronoun

as sí
  1. 1

    himself, herself, itself, themself, themselves

  2. 2

    yourself, yourselves

Source: English Wiktionary, Spanish section, dump of September 2, 2026 (CC BY-SA 4.0).

How Spanish dictionaries define it

adverb: 1. Palabra usada para expresar afirmación. 2. De modo enfático, se usa para introducir una afirmación.

noun: 1. Acción o efecto de aceptar, dar permiso o afirmar.

pronoun: 1. Pronombre personal de tercera persona del singular o plural después de preposiciones.

conjunction: 1. Implica condición o hipotesis 2. Equivale a cuanto si es usado en expresiones ponderativas. 3. Se usa para expresar asombro o sorpresa. 4. Se usa para expresar negación.

pronoun: 1. Grafía obsoleta de sí.

interjection: 1. Grafía obsoleta de sí.

noun: 1. Séptima nota músical de la escala musical pitagórica o diatónica, situada entre el la y el do.

The definition in the Spanish Wiktionary (Wikcionario), in Spanish.

Source: Spanish Wiktionary (Wikcionario), dump of September 1, 2026 (CC BY-SA 4.0), through kaikki.org.

Forms of si

  • ¿sí canonical
  • síes plural
  • sís plural
  • sis plural

Source: English Wiktionary and Spanish Wiktionary (Wikcionario) (dumps of September 2, 2026 and September 1, 2026).

English words that translate to si

Source: the translation tables of the English Wiktionary, dump of September 2, 2026.

How common is si in Spanish?

si appears 3,890 times per million words in written Spanish.

Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).

What to look up after si