a structure built by a bird for laying eggs in and sheltering its young

a place or structure where other creatures, e.g. insects, breed or shelter

a cosy retreat, corner, or hollow

a den or haunt

a nest of forgers

a set of things that fit one inside the other

said of birds: to construct or occupy a nest ready for rearing young

said of tables, etc: to fit one inside the other

to fit (a set of tables, etc) one inside the other

to insert (lexical, linguistic, or computer data) within a hierarchically arranged framework, typically in a subordinate position