Word

嫡室

ちゃくしつ
one's legal wife; legitimate wife
Word

嫡嗣

ちゃくし
legitimate heir
Word

嫡妻

ちゃくさい
one's legal wife; legitimate wife
Word

向かい腹

当腹、嫡腹
むかいばら
child born to one's legal wife (as opposed to one's concubine, etc.)