could

Meanings

1. simple past of can
2. conditional of can
3. Used as a past subjunctive (contrary to fact).
4. Used to politely ask for permission to do something.
5. Used to politely ask for someone else to do something.
6. Used to show the possibility that something might happen.
7. Used to suggest something.
8. past participle of can

1. Something that could happen, or could be the case, under different circumstances; a potentiality.

Etymology

From Middle English coude, couthe, cuthe, from Old English cūþe, past indicative and past subjunctive form of cunnan (“to be able”) (compare related cūþ, whence English couth). Cognate with German konnte, Swedish kunde. The -l- in the spelling was added in the early 16th century by analogy with should and would; this analogy formerly affected the pronunciation as well and was probably assisted by the tendency for /l/ to be lost in those words (and so not written, leading to shudd, wode, etc).