1the greater number:in the majority of cases all will go smoothly [as modifier]:it was a majority decision
British the number by which the votes cast for one party or candidate exceed those for the next:Labour retained the seat with a majority of 9,830
a party or group receiving the greater number of votes.
US the number by which votes for one candidate are more than those for all other candidates together.
2 [mass noun] the age at which a person is legally a full adult, usually either 18 or 21:kids get control of the money when they reach the age of majority
3the rank or office of a major.
be in the majority
belong to or constitute the larger group or number:publishing houses where women are in the majority