metronymic (n.)

by 1841, "a name derived from the name of a mother or maternal ancestor;" by 1844 as an adjective, from Late Greek metrōnymikos "named for one's mother," from mētēr (genitive mētros) "mother" (see mother (n.1)) + onyma "name" (from PIE root *no-men- "name"). Related: Metronymically (1822).