[master key] {n. phr.} A key that opens a set of […]

[master of ceremonies] or [M.C.] or [emcee] {n.} The person in […]

[mastermind] {n.} A person who supplies the intelligence for a project […]

[matelot] {n.} Sailor (from the French).

[matter of course] {n. phr.} Something always done; the usual way; […]

[matter of fact] {n. phr.} Something that is really true; something […]

[matter of opinion] {n. phr.} Something that may or may not […]

[matter of record] {n. phr.} A fact or event that is […]

[means to an end] {n. phr.} An action leading to some […]

[meat and two veg] {n.} Literally a traditional meal consisting of […]