requiring effort or concentration; complex and not easy to answer or solve; "raised serious objections to the proposal"; "the plan has a serious flaw"
of great consequence; "marriage is a serious matter"
concerned with work or important matters rather than play or trivialities; "a serious student of history"; "a serious attempt to learn to ski"; "gave me a serious look"; "a serious young man"; "are you serious or joking?"; "Don't be so serious!"
(often followed by `for') in exchange or in reciprocation; "gave up our seats on the plane and in return received several hundred dollars and seats on the next plane out"; "we get many benefits in return for our taxes"
the magnitude of sound (usually in a specified direction); "the kids played their music at full volume"
a publication that is one of a set of several similar publications; "the third volume was missing"; "he asked for the 1989 volume of the Annual Review"
the amount of 3-dimensional space occupied by an object; "the gas expanded to twice its original volume"
a relative amount; "mix one volume of the solution with ten volumes of water"