dé|colle|tage «DAY kol TAHZH, -ko luh-; DEHK luh-», noun.
1. the neck of a dress cut low so as to leave the neck and shoulders exposed: »
Décolletage has probably caused less stir than almost any facet of women's clothing (Newsweek).
2. a dress or blouse cut in this way.
Useful english dictionary. 2012.