noun
birdhouse; nest box; bird box
A box placed for birds to nest in, often in gardens or parks.
庭に巣箱をかけたら、シジュウカラが入った。
When I put up a birdhouse in the garden, a great tit moved in.
noun
Specifically a man-made box for keeping bees; see also 養蜂箱.
See also: 養蜂箱
この巣箱にはミツバチがたくさんいる。
There are many honeybees in this beehive.