お宅
おたく · otaku · JLPT N4 · noun
house
🏠 お宅 = honorific o + taku (residence): your honourable home
宅 (taku) means residence, as in 自宅 (jitaku, one's own home) and 帰宅 (kitaku, going home). Adding polite お makes it someone else's home. The slang otaku (obsessive fan) grew from fans addressing each other with this stiff, formal word.