noun
mapping pen; crowquill pen
A dip pen with a small, rounded nib, traditionally used for fine lines in drafting, mapping, and manga inking.
漫画家は丸ペンで細かい線を描く。
Manga artists draw fine lines with a mapping pen.
製図には丸ペンがよく使われていた。
Mapping pens were often used for drafting.