slit pocket

基本解释

A slit in a garment, as in the back seam of a pocket.
開衩，衩：衣服上的狹長口子，如在口袋的後部縫口內。
odict.net
Flap pockets are additional fabric on covering the outside of the pocket opening. A high quality pocket allows both a slit pocket and flap pocket.
通常，滾邊開叉口袋是一種理石裝飾品，帽邊口袋是附在口袋外延的附加材料。
blog.sina.com.cn
It is required to be double-besomed so that it becomes a slit pocket when the flap is inserted into the pocket. It gives alternate looks on a single suit.
優質口袋既可以儅細縫口袋，又可以儅帽邊口袋，所以在一套衣服上有多種選擇的外觀。
blog.sina.com.cn