背後
はいご · haigo · JLPT N1 · noun
rear
背後 = 背 (back of the body) + 後 (behind): back + behind, so the rear is doubly covered
Both characters point backward. 背 is the back of the body, and 後 means behind or after. Read haigo, the compound stacks two words for rear into one.
背 — north 北 (phonetic) + flesh 月/肉
Originally a phono-semantic compound: 月 (a form of 肉, 'flesh/body') gives the meaning 'back of the body,' while 北 supplies the sound. Interestingly, 北 itself depicted two people back-to-back and once meant 'back'; when it was borrowed for 'north,' 背 was created with the flesh radical to keep the original sense.