訓 でこ ・ 音 トツ 🔊
Sino-Vietnamese: đột
A pictograph of a shape with its middle sticking up, the opposite of 凹 (concave).
Stroke data: KanjiVG (CC BY-SA 3.0) — kanjivg.tagaini.net
凸レンズで光を集める。 (とつれんずでひかりをあつめる)
A convex lens gathers light.