mammo-comb. form

Stress is usually determined by a subsequent element and vowels may be reduced accordingly; see e.g.
mammogram n.Origin: Either (i) formed within English, by derivation. Or (ii) a borrowing from Latin, combined with an English element. Etymons: mamma n.; Latin mamma , -o- connective.
Etymology: < mamma n. or its etymon classical Latin mamma + -o- connective. Compare earlier masto- comb. form2.Formations are not found before the 20th cent. (The first element of mammothrept n. is not primarily from the etymon of mammo- comb. form.) Combined with second elements ultimately of Greek origin (although mammo- is itself ultimately of Latin origin).
This entry has been updated (OED Third Edition, June 2000; most recently modified version published online December 2018).