phrasal
1. obsolete : in the exercise of an authority or the performance of an authorized or delegated act
the Moor himself … is in full commission here for Cyprus — Shakespeare
2. or into commission of an office or public trust : under the authority of a commission or commissioners (as during the abeyance of the incumbent)
to usurp to itself the executive power of the king and in effect to put the kingship into commission — S.B.Chrimes
3. of a ship : equipped, manned, and under command in readiness for active service
warships will remain in commission when not refitting
4. : in use or service or in condition for service
put the old car back in commission for a time