in concert

noun

1. a public musical performance in which a number of singers or instrumentalists, or both, participate.
2. a public performance, usually by an individual singer, instrumentalist, or the like; recital: The violinist has given concerts all over the world.
3. 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.

adjective

4. designed or intended for concerts: concert hall.
5. performed at concerts: concert music.
6. performing or capable of performing at concerts: a concert pianist.

verb (used with object)

7. to contrive or arrange by agreement: They were able to concert a settlement of their differences.
8. to plan; devise: A program of action was concerted at the meeting.

verb (used without object)

9. to plan or act together.

Idioms

10. in concert, together; jointly: to act in concert.

noun (ˈkɒnsɜːt, -sət)

1. 1. a performance of music by players or singers that does not involve theatrical stagingCompare recital (def. 1)
   2. (as modifier)a concert version of an opera
2. agreement in design, plan, or action
3. in concert
   1. acting in a co-ordinated fashion with a common purpose
   2. (of musicians, esp rock musicians) performing live

verb (kənˈsɜːt)

4. to arrange or contrive (a plan) by mutual agreement

n.

1660s, “agreement, accord, harmony,” from French concert (16c.), from Italian concerto “concert, harmony,” from concertare “bring into agreement,” in Latin “to contend, contest, dispute,” from com- “with” (see com-) + certare “to contend, strive,” frequentative of certus, variant past participle of cernere “separate, decide” (see crisis).

Before the word entered English, meaning shifted from “to strive against” to “to strive alongside.” Sense of “public musical performance” is 1680s. But Klein considers this too much of a stretch and suggests Latin concentare “to sing together” (from con- + cantare “to sing”) as the source of the Italian word in the musical sense.

Together, jointly, as in They worked in concert on the script, or When mind is in concert with body, one can accomplish a great deal. This expression uses concert in the sense of “an agreement of two or more persons.” [Early 1700s]