Where does “si” come from?

si (Portuguese) comes from Spanish sí, from Old Spanish sy, from Latin sīc, from Latin sice, from Latin sī, from Proto-Italic sei, from Proto-Indo-European só — this; that.

si (Portuguese): oneself, yourself, himself, herself, itself,...

Definitions

  1. oneself, yourself, himself, herself, itself,...

Ancestry of “si”, step by step

si traces back through 3 separate lines of ancestry.

via Spanish

StepLanguageWordMeaning
1Spanishyes, affirmation. Commonly used to respond...
2Old Spanishsyyes in response to a question
3Latinsīcyes, indeed (If answering a question)
4Latinsice
5Latinif, supposing that
6Proto-Italicseiso, thus
7Proto-Indo-Europeanthis; that

via Portuguese sim

StepLanguageWordMeaning
1Portuguesesimyes; indeed; do; yes; yea
2Old Portuguesesiyes, affirmatively
3Latinsibithe dative of the reflexive pronoun meaning to...
4Proto-Indo-Europeansébʰye
5Proto-Indo-Europeanswéself

via Latin Sancte Iohannes

StepLanguageWordMeaning
1LatinSancte Iohannes
Every word from Proto-Indo-European Every word from Proto-Italic seiEvery word from Latin