Concert, v. t. [imp. & p. p. Concerted; p. pr. & vb. n. Concerting.]
Etymology: [F. concerter, It. concertare, conertare, prob. from L. consertus, p. p. of conserere to join together; con- + serere to join together, influenced by concertare to contend; con- + centare to strive; properly, to try to decide; fr. cernere to distinguish. See Series, and cf. Concern.]
1. To plan together; to settle or adjust by conference, agreement, or consultation. It was concerted to begin the siege in March. Bp. Burnet.
2. To plan; to devise; to arrange. A commander had more trouble to concert his defense before the people than to plan . . . the compaign. Burke.
2 other Webster entries under this spelling
Concert, v. i.
To act in harmony or conjunction; to form combined plans. The ministers of Denmark were appointed to concert with Talbot. Bp. Burnet
Concert, n.
1. Agreement in a design or plan; union formed by mutual communication of opions and viewa; accordance in a scheme; harmony; simultaneous action. All these discontens, how ruinous soever, have arisen from the want of a due communication and concert. Swift.
2. Musical accordance or harmony; concord. Let us in concert to the season sing. Cowper.
3. A musical entertainment in which several voices or instruments take part. Visit by night your lady's chamber window With some sweet concert. Shak. And boding screech owls make the concert full. Shak. Concert pitch. See under Pitch.
Shades of meaning
Fernald lists concert only as an antonym, under collision.
He lists it without comment; the entries above explain its neighbors.