VIII uncommon noun (1) adjective (1) noun 1. the cardinal number that is the sum of seven and one Synonymseight8eightereighter from Decaturoctadogdoadoctonaryoctet adjective 1. being one more than seven Synonymseight8 Similarcardinal Related words Broader terms digit WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.