A man is an adult male human being. The plural of man is men.
Larry was a handsome man of about 50.
Two men got on the bus.
Man is sometimes used to refer to human beings in general. For example, instead of saying ‘Human beings are destroying the environment’, you can say ‘Man is destroying the environment’. When man has this meaning, don't use ‘the’ in front of it.
Man is always searching for new knowledge.
Massage is one of the oldest forms of treatment known to man.
Men is sometimes used to refer to all human beings, considered as individuals.
All men are born equal.
Darwin concluded that men were descended from apes.
Mankind is used to refer to all human beings, considered as a group.
His only desire is to help mankind.
Some people do not like the use of man, men, and mankind to refer to human beings of both sexes, because they think it suggests that men are more important than women. You can use people instead.
All people are born equal.
'mankind' also found in these entries (note: many are not synonyms or translations):