Definition, synonyms and related words
Something that could happen, or could be the case, under different circumstances; a potentiality.
"If we had taken a different route, we could have arrived before sunset."
In plain English: There is no noun called could because it is only used as a verb to talk about possibility or ability.
"There is just not enough room in the car for all our luggage and two could fit comfortably if we moved some boxes to the trunk."
simple past tense of can
"When I was young, I could run very fast."
Could comes from Old English cūþe, a past form of the verb meaning "to be able." Its modern spelling with an 'l' was added in the 16th century to match the patterns of should and would.