What is a "modesty piece"?

AprilDBradshaw

On the Alfred Angelo website, a lot of their dresses say it can have "optional spaghetti straps or modesty piece". What is a modesty piece?

ring_pop

It's a panel that goes under the corset straps so that you don't see skin through the straps.

kellya01

Sometimes on v-neck dresses, they include a snap-in or hook-in piece over the v-neck so that women with bustier chests can have material over the v-neck to keep the girls from being too "out there."  It can also refer to the corset back like PP said.