8 very common adjective (1) noun (1) adjective 1. being one more than seven Synonymseightviii Similarcardinal noun 1. the cardinal number that is the sum of seven and one SynonymseightVIIIeightereighter from Decaturoctadogdoadoctonaryoctet Related words Broader terms digit WordNet 2.1 (Princeton University). WordNet 2.1 Copyright Princeton University. All rights reserved.