ogdoad(n = noun.quantity) 8, eight, eighter, eighter from decatur, octad, octet, octonary, viii - the cardinal number that is the sum of seven and one;
is a kind of digit, figure
A thing made up of eight parts. Milman. [1913 Webster]
ogdoad, n. a group of eight.
Etymology:
LL ogdoas ogdoad- f. Gk ogdoas -ados f. ogdoos eighth f. okto eight