Since it was essential that a masquerade costume be decollete, she had devised a backless costume, the front cut to display her over-full bust and with one long sleeve to cover her right arm.
-- Betty Smith, A Tree Grows in Brooklyn
There was a pearl-handled fan made of large, colored feathers; there was a faded silk, cream-colored parasol; there was a long, tea-colored ruffled voile dress which had huge pleats and a decollete neck-line; and there was a pair of fragile, high-heeled slippers.
-- Richard Wright, The Outsider
Decollete is a loan word from the French décolleter, "to expose the neck," from de + collet "collar of a dress."