Placket:
A placket is an opening in the upper part of trousers or skirts, or at the neck or sleeve of a garment. Plackets are almost always used to allow clothing to be put on or removed easily, but are sometimes used purely as a design element. Modern plackets often contain fabric facings or attached bands to surround and reinforce fasteners such as buttons, snaps, or zippers. [Wikipedia]
My wife, a former professional tailor, mentioned it today, and it’s a word I’d never heard.
