ogdoad

from WordNet (r) 3.0 (2006)

ogdoad
    n 1: the cardinal number that is the sum of seven and one [syn:
         {eight}, {8}, {VIII}, {eighter}, {eighter from Decatur},
         {octad}, {ogdoad}, {octonary}, {octet}]

from The Collaborative International Dictionary of English v.0.48

ogdoad \og"do*ad\ ([o^]g"d[-o]*[a^]d), n. [Gr. 'ogdoa`s,
   'ogdoa`dos, from 'oktw` eight.]
   A thing made up of eight parts. --Milman.
   [1913 Webster]

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