直線
ちょくせん · chokusen · JLPT N2 · noun
straight line
📏 直 (choku, straight) + 線 (sen, line) = chokusen, a straight line
直 means straight or direct, as in 直接 (chokusetsu, direct). Add 線, line, and the compound names a straight line.
直 — 十 ten + 目 eye + 乚 hidden line
Originally depicted an eye (目) looking straight along a vertical line, suggesting a direct, unswerving gaze. The form combines 目 'eye' with strokes indicating straightness. From this came the meanings 'straight,' 'upright,' and by extension 'honest' or 'direct.'