Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
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.