may

Multiple Entries:
  may    May  

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.

Concise Oxford English Dictionary © 2008 Oxford University Press:
May/meɪ/

▶noun the fifth month of the year.

– origin OE, from OFr. mai, from L. Maius (mensis) ‘(month) of the goddess Maia’.