-mastiacomb. form
Primary stress is attracted to the first syllable of this combining form and vowels may be reduced accordingly; see e.g.
polymastia n.Origin: A borrowing from Greek, combined with an English element. Etymons: Greek μαστός , -ia suffix1.
Etymology: < ancient Greek μαστός breast (see masto- comb. form2) + -ia suffix1. Compare scientific Latin forms in -mastia . Compare -mazia comb. form.This combining form is of limited distribution, being virtually restricted to the words gynaecomastia , micromastia , pleiomastia , and polymastia . It was first used in the mid 19th cent. Gynaecomastia and micromastia both have earlier synonyms in -mazia comb. form; pleiomastia and pleiomazia , however, are first recorded in the same source with distinct meanings (see pleio- comb. form).
This is a new entry (OED Third Edition, March 2001; most recently modified version published online March 2021).