Maternal means to do with a mother, or motherly in feeling. Maternal instinct, maternal grandmother, maternal health.
Maternal grandmother means your mother's mother, which is a useful precision English otherwise lacks. Maternal mortality is one of the sharpest measures of a health system there is.
1adjectivematernalTo do with a mother, or motherly in feeling.
“She had strong maternal feelings towards the orphaned lambs.”
maternal is a quality.
Middle French maternel comes from Latin maternus, from mater, a mother.
Proto-Indo-European
*méh₂tēr
Latin
māternālis — maternal
Middle French
maternel — maternal
Middle English
maternal
English, today
maternal
The adjective is derived from Late Middle English maternal, maternall, from Middle French maternel (“maternal”) (modern French maternel (“maternal; native”)), or from its etymon Latin māternālis (“maternal”), from Latin māternus (“maternal; related to the mother or her side of the family”) + -ālis. Māternus is derived from māter (“mother”) (ultimately from Proto-Indo-European méh₂tēr (“mother”)) + -rnus. The English word is cognate with Italian maternale, materno, Portuguese maternal, materno, Spanish maternal, materno. The noun is derived from the adjective.
Etymology from Wiktionary, CC BY-SA