- pt. of can: he gave what he could give
- used as a modal auxiliary in verbal phrases with present or future time reference, generally equivalent to can in meaning and use, with the following functions:
- expressing esp. a shade of doubt or a lesser degree of ability or possibility: it could be so
- expressing a lesser degree of permission: could I go?
- forming the present conditional: it would help if he could wait
- forming the past conditional: he would have left if he could
- expressing or suggesting politely less certainty than can: could you wait?
Origin of couldaltered (infl. by would, should) from Middle English coud from Old English cuthe (akin to Gothic kuntha, Old High German konda, Old Norse kunna), past tense of cunnan, to be able: see can