Wiktionary
mama bear
alt. 1 A female bear currently rearing one or more cubs. 2 (context by extension slang English) A woman, especially a mother, who is extremely protective of a child or children. n. 1 A female bear currently rearing one or more cubs. 2 (context by extension slang English) A woman, especially a mother, who is extremely protective of a child or children.
Usage examples of "mama bear".
He would get up in the morning and announce that Mommy was Mama Bear, Daddy was Papa Bear, and he was Baby Bear.
A mama bear protecting her cub, Jenny rounded on Max before she shifted to wrap her arms around Laine.
The tearstains had her leaping forward like a mama bear to her threatened cub.