a suffix occurring in loanwords from Greek denoting a group or unit comprising a certain number, sometimes of years: dyad; triad .
a suffix meaning “derived from,” “related to,” “concerned with,” “associated with” (oread), introduced in loanwords from Greek (Olympiad; oread), used sporadically in imitation of Greek models, as Dunciad , after Iliad .
word-forming element denoting collective numerals (cf. Olympiad), plant families, and names of poems, from Greek -as (genitive -ados), a suffix forming fem. nouns; also used in fem. patronymics (Dryad, Naiad, also, in plural, Pleiades, Hyades).