décolletage
/ˌdeɪkɒlˈtɑːʒ/noun
1- a low neckline on a woman's dress or top（女裙或女上装的）低领口。
1.1
- a woman's cleavage as revealed by such a neckline（女性穿低胸衣服露出的）乳沟。
词源
late 19th cent.: French， from décolleter 'expose the neck'， from dé- (expressing removal)+collet 'collar of a dress'.