a neckline on a woman's garment, as a dress, with a high back and a low-cut front with two curved edges resembling the conventionalized shape of a heart.
Origin of sweetheart neckline
First recorded in 1940–45
Also called sweetheart neck.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
British Dictionary definitions for sweetheart neckline
a neckline on a woman's dress that is low at the front and shaped like the top of a heart
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012