
Spanish word poder comes from Latin sum ((copulative) I am, exist, have (with dative).), Latin -ius, Proto-Italic *potis
sum (Latin)
(copulative) I am, exist, have (with dative).
-ius (Latin)
Genitive suffix for some irregular pronouns. Forming adjectives from nouns.
*potis (Proto-Italic)
potis (Latin)
Able, capable, possible.
possum (Latin)
I am able, can.
*potēre (Vulgar Latin)
poder (Spanish)
(El Salvador, colloquial, reflexive) to be familiar with something, or with somebody's personality. To be able, can Authorization. Power, reign. Proxy (written certificate of authority to act for another).