糸いと印じるし

noun

conspicuous thread mark; thread used to make seams stand out

A thread sewn into fabric to make seams or stitching lines clearly visible, often used in tailoring or decorative work.

• 仮かり縫ぬいのときに糸いと印じるしを使つかって、本ほん縫ぬいの位い置ちをわかりやすくする。