noun
Oil-based marker that writes on many surfaces and is water-resistant. Often used for labeling or outdoor signs.
段ボールに油性マジックで名前を書いた。
I wrote my name on the cardboard box with a permanent marker.
油性マジックは水に濡れても消えにくい。
Permanent markers don't easily come off even when wet.
Compound of 油性 (oil-based) and マジック, from the Magic Marker brand, which became a generic term for permanent markers in Japanese.