正午
しょうご · shougo · JLPT N3 · noun
noon
🕛☀️ 正午 = exactly + noon (the horse hour, 11am-1pm)
正 means exact or correct; 午 is the horse sign of the old zodiac clock, covering 11am-1pm. So 正午 is the exact middle of the horse hour: 12:00. The same 午 appears in 午前 (gozen, a.m. = before noon) and 午後 (gogo, p.m. = after noon).
正 — one 一 + stop 止
Originally an ideograph showing a foot (止) advancing toward a target line (一), meaning 'to march straight toward' a city or goal. From this came the senses 'upright,' 'correct,' and 'proper.' The military sense survives in 征 (to campaign), which took over the original 'march' meaning.