might

Multiple Entries:
  might    may  

Concise Oxford English Dictionary © 2008 Oxford University Press:
might1

▶modal verb (3rd sing. present might) past of may1.

• 1 used in reported speech to express possibility or permission.

  ■ expressing a possibility based on an unfulfilled condition.

  ■ expressing annoyance: you might have told me!

• 2 used politely or tentatively in questions and requests.

  ■ asking for information: who might you be?

• 3 used to express possibility or make a suggestion.

usage: On the distinction between might and may, see usage at may1.

Concise Oxford English Dictionary © 2008 Oxford University Press:
might2

▶noun great power or strength.

– phrases
with might and main with all one's strength or power.

– origin OE miht, mieht, of Gmc origin; rel. to may1.

Concise Oxford English Dictionary © 2008 Oxford University Press:
may1

▶modal verb (3rd sing. present may; past might /mʌɪt/)

• 1 expressing possibility.

• 2 expressing permission.

• 3 expressing a wish or hope.

– phrases
be that as it may nevertheless.
that is as may be that may or may not be so.

– origin OE mæg, of Gmc origin, from a base meaning ‘have power’.

usage:
Traditionalists insist that one should distinguish between may (present tense) and might (past tense) in expressing possibility: I may have some dessert if I'm still hungry; she might have known her killer. However, this distinction is rarely observed today, and may and might are generally acceptable in either case.
On the difference in use between may and can, see usage at can1.

Concise Oxford English Dictionary © 2008 Oxford University Press:
may2

▶noun the hawthorn or its blossom.

– origin ME: from May.