Move to and fro is a phrase that describes a back-and-forth motion. The crossword solutions for this term are SWING (5 letters), wave (4 letters), SWAY (4 letters), ROCK (4 letters), OSCILLATE (9 letters), SHUTTLE (7 letters), wigwag (6 letters), and VIBRATE (7 letters). These words all describe a similar action, which is a repetitive movement in one direction and then the other. SWING, wave, and SWAY refer to a motion of the arms or body, while ROCK, OSCILLATE, SHUTTLE, wigwag, and VIBRATE refer to a motion of an object or machine.