noun
A trademarked name often used generically for felt-tip pens in Japan. Wasei-eigo from 'sign pen'.
wasei-eigo (Japanese-coined English), from sign pen
プレゼントにカラフルなサインペンを買った。
I bought colorful felt-tip pens as a gift.
このサインペンは水性
This felt-tip pen uses water-based ink.