may

I UK [meɪ] / US modal verb ***

Summary:

May is usually followed by an infinitive without "to": It may rain. Sometimes may is used without a following infinitive: I'd like to make one or two comments, if I may.
May does not change its form, so the third person singular form does not end in "-s": He may arrive this afternoon. Questions and negatives are formed without "do": May I make a suggestion? ♦ She may not understand. The negative form may not is sometimes shortened to mayn't by British speakers of English, but it is not common.
May has no participles and no infinitive form. There is no past tense, but may have followed by a past participle can be used for talking about past possibilities: She may have changed her mind and decided not to come. When indirect speech is introduced by a verb in the past tense, might is used as the past tense of may: I asked if I might see the paintings. There is no future tense, but may is used for talking about future possibilities: I may go to London next week.
Collocations:
Both may and might are used for expressing the idea that perhaps something is true or that perhaps something will happen, but might is more common in conversation, and may is more common in writing.
Might is often used for suggesting that a possibility is rather unlikely or not at all definite: You might have an accident.
May and might are both used in polite requests, remarks, and offers: May I see that? ♦ Might I make a suggestion?

1) used for showing possibility

a) used for saying that there is a possibility that something is true or that something will happen

There may be an easier way of solving the problem.

The injury may have caused brain damage.

I may not be able to play on Saturday.

You may be asked to show your passport.

Some fir trees may grow up to 60 feet high.

b) formal used for saying that it is possible to do something in a particular way

The bill may be paid by cheque or by credit card.

The total may be calculated by two different methods.

2) be allowed to do something

a) spoken used for politely asking someone to let you do something

May we come in now?

May I use your phone?

b) formal used for saying that something is allowed

Visitors may use the swimming pool between 5.30 and 7.30 pm.

You may take a short break now.

3) spoken used in polite requests or offers used when making a polite request or offer

May I have a biscuit?

May I help?

May we offer you a glass of wine?

May I see your ticket, please?

See:

can

4) spoken used in polite remarks or suggestions used when making a polite remark or suggestion

may I say/ask/suggest etc:

May I say a word of thanks to all those who helped today.

May I suggest a better idea?

if I may:

Let me, if I may, introduce you to my manager, Jim Doyle.

5) formal used for showing a purpose used for saying that someone does something in order to achieve a particular purpose

The dried fruit may be used through the winter.

6) formal used for expressing a wish used for expressing a hope or a wish

May peace and prosperity return to this troubled land!

•

I may say/add — British

spoken used for emphasizing what you are saying

I sacrificed a lot, I may say, to help him.

may ... but — used when you agree that something is true, but you argue that this does not change the main fact that you are stating

The school may not be as good as it was, but it is still popular.

may (very) well/easily — used for saying that something is fairly likely to be true or is fairly likely to happen

What you say may very well be true.

A small technical error may easily result in a serious accident.

it may well be that:

It may well be that the information is not available.

- if I may say so

- may as well

See:

be

II UK [meɪ] / US noun [uncountable]

the hawthorn tree, or its flowers