meh₂-tér-₂
“mother, origin, source”maternal, maternity, matrix, matter
Extended form of *méh₂tēr giving Latin māternus, English maternal, maternity, matrix, matter.
Discussion
The PIE form *meh₂-tér- (mother, origin, source) is a kinship agent noun parallel to *ph₂tḗr (father), formed with the same *-tér- suffix. Unlike *ph₂tḗr, which derives from a root meaning "to protect," the mother-word may derive from a nursery word *meh₂- (mama) — one of the few PIE reconstructions where sound symbolism and baby-talk may have played a role in word formation.
The cognate set matches the father-word in perfection: Latin māter, Greek mḗtēr, Sanskrit mātár-, Old English mōdor, Old Irish máthir, Lithuanian mótė, Old Church Slavonic mati — all continuing *méh₂tēr with textbook regularity.
Latin māter generated: maternal, matriarch, matrimony (the legal state of motherhood — contrast patrimony, father-wealth), matrix (the womb — then any formative enclosure, hence the mathematical matrix and the film title), matron (a married woman/mother-figure), material (from materia, "substance" — originally "timber," conceived as the mother-stuff from which things are made), and matter itself (the same word as material — the stuff of which reality is composed is, etymologically, the mother-substance).
The word alma mater ("nourishing mother" — the university as nurturing parent) and metropolis (mḗtēr + pólis, "mother-city") extend the family into institutional vocabulary.
English mother (OE mōdor, from PGmc *mōdēr) continues the root natively. German Mutter, Dutch moeder, and the Scandinavian forms confirm the pan-Germanic distribution.
The nursery-word hypothesis — that *meh₂- derives from the babbling sounds (ma-ma) that infants make while nursing — is debated but phonetically plausible. If correct, "mother" would be one of the few PIE words where the proto-language preserved a sound directly motivated by infant physiology rather than adult convention.