Noah Webster
Den
DEN, noun
1. A cave or hollow place in the earth; usually applied to a cave, pit, or subterraneous recess, used for concealment, shelter, protection or security; as a lions den; a den of robbers or thieves.
The beasts go into dens. The children of Israel made themselves dens. Job 37:8. Judges 6:2.
2. As a termination, in names of places, it denotes the place to be in a valley or near a wood.
DEN, verb intransitive To dwell as in a den