A brassiere designed to elevate the breasts and enhance the cleavage(noun)
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Use "push-up bra" in a sentence
"Wonderbra, the push-up bra that has been a huge success, launched an unusual RELATE campaign in 1998.10 Print ads and posters show an underwear-clad model in an action pose, airborne, hair flying."
"The tanga covered the worst of the cellulite on my thighs and the push-up bra was doing its job admirably."