Décolleté is the sister word to décolletage. As a noun it is the low top edge of a woman’s dress — the neckline cut to show the neck, shoulders, and part of the chest. As an adjective it means cut that way (a décolleté dress), or, of a person, wearing such a dress. English borrowed both from French décolleter, “to bare the neck and shoulders.” In real talk, most English speakers still say “low-cut”; you will see décolleté on clothing labels, in fashion writing, and in older novels. It does not mean “sexy” by itself — it only says how the neckline sits. Though actually, even careful writers mix décolleté and décolletage. If you keep a simple picture — décolleté as the describing word, décolletage as the neckline itself — you will be close enough, and nobody in ordinary life is marking the difference. The last e has a mark in careful spelling; people say it a bit like “day-coll-tay.”

低胸的；作名詞時即低胸領口