1 a : of or relating to a mother : MOTHERLY
1 b always used before a noun : of or relating to a woman who is having a baby
Doctors are concerned about the effects of the drug on maternal health.
2 always used before a noun : related through the mother
his maternal grandparents [=the parents of his mother]
a maternal aunt/uncle
— maternally adverb
She smiled at them maternally.
maternally inherited genes