Wiktionary
den mother
n. 1 an adult (female) leader of a Cub Scout den 2 a person who plays the role of leader or protector of a group
WordNet
den mother
n. a woman who supervises a den of Cub Scouts
Usage examples of "den mother".
Yet, with a snap of Fate's fingers, a roll of Fate's dice, she was the den mother, the group leader, the general leading the charge.
That's a little something I learned during my years as a den mother with the Brownies.
Their den mother is a woman called Monica: a willowy, brown-eyed hive queen with raster-burned corneal implants and a dry, sardonic delivery that can corrode egos like a desert wind.
The den mother's house was a mile up the road and going was fine, yes, excellent, because you walked in the late afternoon daylight.