Synonyms for Octet (same or very similar meaning)
WordNet sense 1 (the cardinal number that is the sum of seven and one):
eight, eighter, octad, octonary, ogdoad, VIII, eighter from DecaturWordNet sense 2 (eight performers or singers who perform together):
octetteWordNet sense 3 (eight people considered as a unit):
eightsomeFrom the ODE community, based on WordNetadd/edit