往复运动

Traditional (Taiwan): 往復運動

wǎngfùyùndòng ㄨㄤˇ ㄈㄨˋ ㄩㄣˋ ㄉㄨㄥˋ

    • backwards and forwards action (e.g. of piston or pump)
    • reciprocating motion

Character by character

Sources