A nest or hive where birds or insects lay eggs and raise their young (e.g., bird's nest, beehive).
庭の木に小さな鳥の巣があった。
There was a small bird's nest in the tree in the garden.
蜂の巣が家の軒下にできてしまった。
A beehive has formed under the eaves of the house.
親鳥が巣で子どもを温めている。
The parent bird is warming its chicks in the nest.
A den or lair where an animal lives or hides.
キツネは土手の下に巣を作っている。
A fox has made its den under the embankment.
寒い季節は、動物たちが巣にこもることが多い。
In cold seasons, animals often stay inside their dens.
A haunt or place where a certain kind of people (often undesirable) gather; used in phrases like 'a den of ...'.
その店はスリの巣になっていると聞いた。
I've heard that the shop has become a den for pickpockets.
町の一角が不良たちの巣と化していた。
One corner of the town had become a haunt for delinquents.
A spider's web (the tangled silk threads spun by spiders).
古い倉庫の隅に大きな蜘蛛の巣が張っていた。
A large spider's web was spread in the corner of the old warehouse.
窓に積もった埃に小さな巣ができていた。
A small web had formed in the dust on the window.