denning

noun

1. the cave or other lair of a wild animal
2. a retreat or headquarters, as of thieves; haunt
3. a small, squalid room
4. a small, cozy room in a house, where a person can be alone to read, work, etc.
5. a small, localized unit of Cub Scouts

Etymology: ME < OE denn, lair, pasture, akin to MLowG, place where grass is trodden down, lair < IE base *dhen-, level place

intransitive verb denned, denning den′·ning