insect pin; setting pin
A thin, sharp pin used especially for mounting insects in collections, but also for temporarily holding fabric or other light materials in place.
I fixed the butterfly with an insect pin to make a specimen.
Please secure the fabric with setting pins so it doesn't shift.
Compound of 虫 (mushi, 'insect') and ピン (pin, from English 'pin'). The spelling reflects its primary use in entomology.