Etymology: Partly (i) < Middle French, French concert, †consert (masculine) agreement, accord, pact (late 16th cent.), group of musicians performing together (1608), musical accord, harmony (1630 or earlier), musical performance (1677; 1611 in concert de musique ), and partly (ii) < Italian concerto group of musicians performing together (1519), accord, agreement, pact (1566 or earlier), harmony between things or people (late 16th cent.), performance by a number of musicians playing or singing together (1623; > concerto n.), both ultimately < classical Latin concertāre (see concert v. and discussion at that entry); the French word was probably either borrowed from or influenced by the Italian word. Compare Catalan concert , Spanish concierto (both 15th cent., earliest in sense ‘agreement, accord’), Portuguese concerto (1364), and also Dutch concert (1663), German Konzert (1619 as †concert ), both earliest in music. Compare also Middle French (rare) concerte (feminine) musical accord, harmony (a1374), Middle French, French †conserte conference, conversation (1586). Compare concert v.Forms of the present word are difficult to distinguish from those of consort n.²: forms with -ert are treated at the present entry, and those with -ort at consort n.² The two nouns share a number of senses in common (compare also the parallel constructions in concert beside in consort, concert of music beside consort of music, etc.) and appear to have been confused with one another in early modern English; compare e.g.:1611 R. Cotgrave Dict. French & Eng. Tongues Concert de Musique, a consort of Musicke.

Etymology: Partly (i) < Spanish concertar to arrange, set up, agree (1251), partly (ii) < Middle French, French concerter to arrange (a pact, accord, plan, etc.) by mutual agreement (a1449), to compete, engage in a contest (1541), to make music (1623), to debate, dispute (1670), and partly (iii) < their probable common etymon classical Latin concertāre (intransitive) to engage in a contest, to contend, to fight, to dispute, debate, in post-classical Latin also to strive, to strive alongside or together with < con- con- prefix + certāre to contend (see certation n.). Compare Italian concertare to come to a mutual agreement, to make an accord or pact together (1537–68; perhaps earlier (14th cent.) in a disputed instance in Boccaccio), (of voices or musical instruments) to perform together in harmony (a1647), and also Catalan concertar (c1390), Portuguese concertar (14th cent.). Compare earlier concert n.Although classical Latin concertāre is generally accepted as the etymon of the Romance verbs, the development in the Romance languages of senses relating to harmony (especially in music) is uncertain and disputed, and various attempts have been made to explain it. It has been argued that the usual sense ‘contest, dispute, debate’ of classical Latin verb gave rise to the sense ‘to reach agreement (through discussion)’, and that the musical uses represent a specific sense development of the resulting sense ‘to agree, be in harmony’, while another view sees them as a development from the post-classical Latin sense ‘to strive alongside, work together’. Alternative etymologies from an unrecorded derivative of classical Latin conserere ‘to join together’ and from classical Latin certus determined, settled, sure (see certain adj.) have also been proposed, but neither is supported by the available evidence. For further discussion see New Grove Dict. Music (electronic ed.) (26 Oct. 2011) at concerto.