三角
さんかく · sankaku · JLPT N2 · noun
triangle
🔺 三角 = 三 three + 角 corner: a shape with three corners
三 (san) means three and 角 (kaku) means corner or angle, so the word literally says three corners. The same 角 appears in 直角 (chokkaku, right angle).
三 — three horizontal strokes 一 + 一 + 一
三 is a pictographic numeral: three stacked horizontal lines representing the number three, parallel to 一 (one) and 二 (two). The form has been stable since oracle bone script. It carries no phonetic component; the meaning 'three' is direct and visual.
角 — pictograph of a horn
角 is a pictograph of an animal's horn, with early oracle-bone forms clearly showing the curved, ridged shape of a horn. From 'horn' it extended to mean corner, angle, and by metaphor a role or part (as in a stage role). The reading jiǎo covers most of these senses.