1.
nest
A structure built by birds or other animals to hold eggs or young.
鳥が巣を作っている。
A bird is building a nest.
蜂の巣に気をつけて。
Be careful of the beehive.
蜘蛛の巣がある。
There's a spider web.
燕が巣を作った。
The swallows built a nest.
巣から落ちた雛。
A chick that fell from the nest.
巣箱を設置した。
I installed a birdhouse.
2.
den, hideout
A place where someone or something lives or hides.
犯罪者の巣になっている。
It has become a den of criminals.
悪党の巣。
A hideout of villains.
詐欺師の巣になっている。
It has become a den of swindlers.
敵の巣に乗り込む。
To raid the enemy's hideout.
あの建物は不良の巣になっているから、近づかないほうがいい。
That building has become a hangout for delinquents, so it's best not to go near it.
巣 refers to structures built by animals for shelter or raising young—nests, hives, webs, dens, etc.
COMMON ANIMAL NESTS:
- 鳥の巣: bird's nest
- 蜂の巣: beehive
- 蜘蛛の巣: spider web
- 蟻の巣: ant nest
COMMON EXPRESSIONS:
- 巣を作る: to build a nest
- 巣から落ちる: to fall from the nest
- 巣立つ: to leave the nest (also figurative)
- 巣に戻る: to return to the nest
FIGURATIVE USAGE (SENSE 2):
巣 can mean "den" or "hideout":
- 犯罪者の巣: criminals' den
- 悪の巣窟: den of evil
COMPOUNDS:
- 巣箱: birdhouse
- 巣穴: burrow, lair