noun
plural sleeves
[count] the part of a shirt, jacket, etc., that covers all or part of your arm
see color picture - see also shirtsleeve
a part that fits over or around something to protect it or to hold its parts together
jacket 2b
an ace up your sleeve
have/keep (something) up your sleeve
informal :to have/keep a secret method, trick, etc., that you can use when it is needed
laugh up your sleeve
on your sleeve
informal :in a way that can be clearly seen
roll up your sleeves
US