-ad

-ad¹

1. a suffix occurring in loanwords from Greek denoting a group or unit comprising a certain number, sometimes of years: dyad; triad.

2. 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.

[Gk -ad- (s. of -as), specialization of fem. adjective-forming suffix, often used substantively]

-ad²

var. of -ade¹: ballad.

-ad³

Anat., Zool. a suffix forming adverbs from nouns signifying parts of the body, denoting a direction toward that part: dextrad; dorsad; mediad.

[ < L ad toward, anomalously suffixed to the noun; introduced as a suffix by Scottish anatomist John Barclay (1758-1826) in 1803]

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