also: オーペア
noun
au pair
A young foreign person, typically a woman, who lives with a host family and helps with childcare and light housework in exchange for room, board, and pocket money.
来年、イギリスでオペアとして働く予定です。
Next year, I plan to work as an au pair in the UK.
オペアの受け入れ家庭を探しています。
We are looking for a host family for an au pair.
ベビーシッター is a babysitter who is paid for childcare, while オペア is a cultural exchange participant who lives with the family and receives pocket money.
住み込み means live-in work in general, not specifically the cultural exchange aspect of an au pair.
Loanword from French 'au pair', literally meaning 'on equal terms', referring to the reciprocal arrangement of work for room and board.