往復運動 wǎng fù yùn dòng

DEFINITIONS

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

CHARACTERS

往 wǎng go, depart; past, formerly
復 fù return; repeat; repeatedly
運 yùn luck, fortune; ship, transport
動 dòng move, happen; movement, action