Can.
can1 /kæn; unstressed kən/ Pronunciation Key - Show Spelled Pronunciation[kan; unstressed kuhn] Pronunciation Key - Show IPA Pronunciation auxiliary verb and 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. For auxiliary verb: imperative, infinitive, and participles lacking. For verb (Obsolete): imperative can; infinitive can; past participle could; present participle cun·ning.
–auxiliary verb 1. to be able to; have the ability, power, or skill to: She can solve the problem easily, I'm sure.
2. to know how to: He can play chess, although he's not particularly good at it.
3. to have the power or means to: A dictator can impose his will on the people.
4. to have the right or qualifications to: He can change whatever he wishes in the script.
5. may; have permission to: Can I speak to you for a moment?
6. to have the possibility: A coin can land on either side.
–verb (used with object), verb (used without object) 7. Obsolete. to know.