折り返し， 折返し， おりかえし
1. by return, (call or write back) without delay
2. lapel, cuff, turn-up, flap
3. going back, returning, turn (marathon, swimming, etc.)
4. chorus, refrain
5. shuttle service
6. aliasing (in imaging)
7. back-to-back, BTB
8. wrapping (text on computer...
马上回复(打电话或写信回复)；折返(长跑、游泳等)