noun
placket
A placket is an opening in a garment, typically reinforced, used for fastenings such as buttons or a zipper. This term is a direct loanword used in sewing and fashion contexts.
このシャツのプラケットはボタンで留めるタイプです。
The placket on this shirt is the type that fastens with buttons.
プラケットの縫い方を教えてください。
Please teach me how to sew a placket.