III fairly common noun (1) adjective (1) noun 1. the cardinal number that is the sum of one and one and one Synonymsthree3triothreesometierceleashtroikatriadtrinetrinityternaryterniontriplettercetterzettotreydeuce-ace adjective 1. being one more than two Synonymsthree3 Similarcardinal Related words Broader terms digit WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.