could

[ koo d; unstressed kuh d ]
/ kʊd; unstressed kəd /

verb

a simple past tense of can1.

auxiliary verb

(used to express possibility): I wonder who that could be at the door. That couldn't be true.
(used to express conditional possibility or ability): You could do it if you tried.
(used in making polite requests): Could you open the door for me, please?
(used in asking for permission): Could I borrow your pen?
(used in offering suggestions or advice): You could write and ask for more information. You could at least have called me.

Origin of could

Middle English coude, Old English cūthe; modern -l- (from would1, should) first attested 1520–30

usage note for could

See care.

WORDS THAT MAY BE CONFUSED WITH could

could should would (see usage note at should)

Definition for could (2 of 3)

can 1
[ kan; unstressed kuh n ]
/ kæn; unstressed kən /

auxiliary verb, present singular 1st person can, 2nd can or (Archaic) canst, 3rd can, present plural can; past singular 1st person could, 2nd could or (Archaic) couldst, 3rd could, past plural could.

verb (used with or without object), present singular 1st person can, 2nd can or (Archaic) canst, 3rd can, present plural can; past singular 1st person could, 2nd could or (Archaic) couldst, 3rd could, past plural could; imperative can; infinitive can; past participle could; present participle cun·ning.

Obsolete. to know.

Origin of can

1
before 900; Middle English, Old English, present indicative singular 1st, 3rd person of cunnan to know, know how; cognate with German, Old Norse, Gothic kann; see ken, know1

usage note for can

Can1 and may1 are frequently but not always interchangeable in senses indicating possibility: A power failure can (or may ) occur at any time. Despite the insistence by some, that can means only “to be able” and may means “to be permitted,” both are regularly used in seeking or granting permission: Can (or May ) I borrow your tape recorder? You can (or may ) use it tomorrow. Sentences using can occur chiefly in spoken English. May in this sense occurs more frequently in formal contexts: May I address the court, Your Honor? In negative constructions, can't or cannot is more common than may not : You can't have it today. I need it myself. The contraction mayn't is rare.
Can but and cannot but are formal and now somewhat old-fashioned expressions suggesting that there is no possible alternative to doing something. Can but is equivalent to can only : We can but do our best. Cannot but is the equivalent of cannot help but : We cannot but protest against these injustices. See also cannot, help.

WORDS THAT MAY BE CONFUSED WITH can

can may shall will (see usage note at the current entry) (see usage note at shall)

Definition for could (3 of 3)

can 2
[ kan ]
/ kæn /

noun

verb (used with object), canned, can·ning.

Origin of can

2
before 1000; Middle English, Old English canne, cognate with German Kanne, Old Norse kanna, all perhaps < West Germanic; compare Late Latin canna small vessel

British Dictionary definitions for could (1 of 3)

could
/ (kʊd) /

verb (takes an infinitive without to or an implied infinitive)

used as an auxiliary to make the past tense of can 1
used as an auxiliary, esp in polite requests or in conditional sentences, to make the subjunctive mood of can 1 could I see you tonight?; she'd telephone if she could
used as an auxiliary to indicate suggestion of a course of action you could take the car tomorrow if it's raining
(often foll by well) used as an auxiliary to indicate a possibility he could well be a spy

Word Origin for could

Old English cūthe; influenced by would, should; see can 1

British Dictionary definitions for could (2 of 3)

can 1
/ (kæn, unstressed kən) /

verb past could (takes an infinitive without to or an implied infinitive) (intr)

used as an auxiliary to indicate ability, skill, or fitness to perform a task I can run a mile in under four minutes
used as an auxiliary to indicate permission or the right to something can I have a drink?
used as an auxiliary to indicate knowledge of how to do something he can speak three languages fluently
used as an auxiliary to indicate the possibility, opportunity, or likelihood my trainer says I can win the race if I really work hard

Word Origin for can

Old English cunnan; related to Old Norse kunna, Old High German kunnan, Latin cognōscere to know, Sanskrit jānāti he knows; see ken, uncouth

undefined can

See may 1

British Dictionary definitions for could (3 of 3)

can 2
/ (kæn) /

noun

verb cans, canning or canned

Word Origin for can

Old English canne; related to Old Norse, Old High German kanna, Irish gann, Swedish kana sled

Idioms and Phrases with could (1 of 2)

could

see can (could) do with; see with half an eye, could. Also see under can; couldn't.

Idioms and Phrases with could (2 of 2)

can