nestable

noun

1. the structure made or the place chosen by birds for laying their eggs and sheltering their young
2. 1. the place used by turtles, hornets, fish, etc. for spawning or breeding
   2. the structure made or the place chosen by any of certain wild animals as its home: a squirrel's nest
3. a cozy or snug place in which to live or rest; retreat
4. 1. a haunt or den: used esp. in an unfavorable sense
   2. the people who frequent such a place: a nest of criminals
5. a brood, swarm, or colony of birds, insects, etc.
6. a set or series of similar things, each fitting within the one next larger

intransitive verb

1. to build or live in or as in a nest
2. to fit one into another
3. to hunt for birds' nests: usually in the present participle

transitive verb

1. to make a nest for
2. to place or settle in or as in a nest
3. to fit (an object) closely within another
4. Comput. to embed (a loop, subroutine, etc.) between the first and last instructions of another