Definition of may modal verb from the Oxford Advanced Learner's Dictionary

Oxford3000

may

modal verb
meɪ
 
; meɪ
 
 
negative may not rare short form mayn't
ˈmeɪənt
 
; ˈmeɪənt
 
past tense might
maɪt
 
; maɪt
 
negative might not rare short form mightn't
ˈmaɪtnt
 
; ˈmaɪtnt
 
1 used to say that something is possibleThat may or may not be true.He may have (= perhaps he has) missed his train.They may well win.There is a range of programs on the market which may be described as design aids.2 used when admitting that something is true before introducing another point, argument, etc.He may be a good father but he's a terrible husband.3 (formal) used to ask for or give permissionMay I come in?You may come in if you wish.4 (formal) used as a polite way of making a comment, asking a question, etc.You look lovely, if I may say so.May I ask why you took that decision?If I may just add one thing…5 (formal) used to express wishes and hopesMay she rest in peace.Business has been thriving in the past year.Long may it continue to do so.6 (formal) used to say what the purpose of something isThere is a need for more resources so that all children may have a decent education.
Idioms

be that as it may

(formal) despite that
Synonym
nevertheless
I know that he has tried hard; be that as it may, his work is just not good enough.
Usage noteUsage note: can / mayCan and cannot (or can’t) are the most common words used for asking for, giving or refusing permission:Can I borrow your calculator? You can come with us if you want to. You can’t park your car there.May (negative may not) is used as a polite and fairly formal way to ask for or give permission:May I borrow your newspaper? You may come if you wish. It is often used in official signs and rules:Visitors may use the swimming pool between 7 a.m. and 7 p.m. Students may not use the college car park. The form mayn’t is hardly ever used in modern English.Usage noteUsage note: modal verbsThe modal verbs are can, could, may, might, must, ought to, shall, should, will and would. Dare, need, have to and used to also share some of the features of modal verbs.Modal verbs have only one form. They have no -ing or -ed forms and do not add -s to the 3rd person singular form:He can speak three languages. She will try and visit tomorrow.Modal verbs are followed by the infinitive of another verb without to. The exceptions are ought to, have to and used to:You must find a job. You ought to stop smoking. I used to smoke but I gave up two years ago.Questions are formed without do/does in the present, or did in the past:Can I invite Mary? Should I have invited Mary?Negative sentences are formed with not or the short form -n’t and do not use do/does or did.You will find more help with how to use modal verbs at the dictionary entries for each verb.