Real Dictionary

burrow
countable noun: A burrow is a tunnel or hole in the ground that is dug by an animal such as a rabbit.
verb: If an animal burrows into the ground or into a surface, it moves through it by making a tunnel or hole.
verb: If you burrow in a container or pile of things, you search there for something using your hands.
verb: If you burrow into something, you move underneath it or press against it, usually in order to feel warmer or safer.

burrow in American English
a hole or tunnel dug in the ground by an animal
to make a burrow; dig (in, into, under, etc.)
to make burrows in (the ground)
intransitive verb: to make a hole or passage in, into, or under something
noun: a hole or tunnel in the ground made by a rabbit, fox, or similar animal for habitation and refuge
transitive verb: to put a burrow into (a hill, mountainside, etc.)

burrow in British English
noun: a hole or tunnel dug in the ground by a rabbit, fox, or other small animal, for habitation or shelter
verb: to dig (a burrow) in, through, or under (ground)