Lewis & Short

1. concessus, a, um, Part., from concedo.

2. concessus, ūs, m. [concedo], a permitting, conceding, concession, permission, leave (in good prose, but used only in abl. sing.): Caesaris concessu, Caes. B. G. 7, 20: datur concessu omnium huic aliquis ludus aetati, Cic. Cael. 12, 28: concessu et beneficio illius, id. Fam. 4, 6, 3: concessu et munere deorum, id. Tim. 14 fin.: ipsorum inter ipsos, id. Brut. 21, 84: fratrum, Tac. A. 12, 44.