空き巣【あきす】
empty nest, empty house, empty home, burglary (of an empty house), burglar (who targets empty houses), sneak thief, prowler
巣立ち【すだち】
leaving the nest, going out into the world, becoming independent
古巣【ふるす】
old haunts, former homes
卵巣【らんそう】
ovary
巣立つ【すだつ】
to leave the nest, to go out into the world, to become independent (of one's parents), to graduate (and become a member of society)
営巣【えいそう】
building a nest
病巣【びょうそう】
focus, nidus, lesion
巣箱【すばこ】
birdhouse, nest box, bird box, beehive