A plunge bra is defined by the low, plunging front of it. Unlike a push up bra that may hold your breasts up and may not be appropriate to wear with deep v-neck shirts, blouses or dresses, a plunge bra gives you cleavage but has a low enough cut so it's perfect for lower cut tops. You still get great cleavage and lift, just in a lower cut style.
Because plunge bras are typically worn with outfits that show cleavage, these bras typically come in sexier or classier styles than other bra types. In a variety of seamless bras and embroidered and lace bras, Big Girls Bras (at BiggerBras.com) plunge bras are contemporary in design and you'll find our top designers throughout the collections.
Plunge bras can also vary in how low of a plunge cut they have. Empreinte designs the luxury Very Very Plunge Bra 0864 for a super confident, low plunge look. Freya offers the popular Retro Full Cup Plunge Bra AA3421 with fuller coverage and a higher plunge cut, making it more ideal for a conservative outfit that still needs a low cut - think v neck sweater.
Other popular plunge bras, like the Panache SuperBra Inferno Underwire Plunge Bra 3606, meet in the middle, offering more coverage than deep plunging styles but with enough support to keep you comfortable not to mention near perfect cleavage. You can view all of these great plunge bras and more.