/tooh"euhn froh"/ , adj., n., pl. to-and-fros .
adj.
1. back-and-forth: to-and-fro motion.
n.
2. a continuous or regular movement backward and forward; an alternating movement, flux, flow, etc.: the to-and-fro of the surf.
[ 1820-30; adj. and n. use of adv. phrase to and fro, ME; see FRO (def. 2) ]