writer's callus; writer's bump
A callus that forms on the finger from prolonged writing or drawing pressure.
If you hold a pen for many years, you develop a writer's callus on your middle finger.
His writer's bump hurt, so he stopped writing for a while.
Katakana spelling variant, also common.
Kanji form using 胼胝 (callus); rarely used and may be unfamiliar to many readers.
Compound of ペン (pen) and たこ (callus). The kanji form 胼胝 is a rare ateji for たこ.