Revers

A revers or rever is a part of a garment that is reversed to display the lining or facing outside. The word is borrowed from French "revers", which is reflected in the final "s" being silent. 
The most common form of revers is the lapel. The revers emerged in the 1860s in France as soldiers began unbuttoning the fronts of their uniforms. When the revers became dirty, the uniform could be buttoned up to show a clean front again.