noun
one's in-laws; family by marriage
Often refers to a woman's in-laws after marriage, but can be used for either spouse's marital family.
彼女は婚家との関係に悩んでいる。
She is troubled by her relationship with her in-laws.
婚家のしきたりに従うのは大変だ。
It's hard to follow the customs of one's marital family.
Compound of 婚 (marriage) and 家 (house/family). The exact historical derivation is uncertain, but the word has been used in formal contexts to refer to the family one marries into.