a public musical performance in which a number of singers or instrumentalists, or both, participate.

a public performance, usually by an individual singer, instrumentalist, or the like; recital

The violinist has given concerts all over the world.

agreement of two or more individuals in a design or plan; combined action; accord or harmony

His plan was greeted with a concert of abuse.

designed or intended for concerts

concert hall.

performed at concerts

concert music.

performing or capable of performing at concerts

a concert pianist.

to contrive or arrange by agreement

They were able to concert a settlement of their differences.

to plan; devise

A program of action was concerted at the meeting.

to plan or act together. ?

in concert

together; jointly

to act in concert.