Merriam-Webster's Collegiate® Dictionary, 11th Edition
BURROW
I. noun
Etymology: Middle English borow
Date: 13th century
a hole or excavation in the ground made by an animal (as a rabbit) for shelter and habitation,
II. verb
Date: 1602
transitive verb to hide in or as if in a burrow,
2. to construct by tunneling, to penetrate by means of a burrow, to make a motion suggestive of burrowing with ; nestle , intransitive verb to conceal oneself in or as if in a burrow,
2. to make a burrow, to progress by or as if by digging, to make a motion suggestive of burrowing ; snuggle , nestle , burrower noun