[rein] n [ME reine, fr. MF rene, fr. (assumed) VL retina, fr. L retinere to restrain--more at retain] (14c) 1: a strap fastened to a bit by which a rider or driver controls an animal--usu. used in pl.
2. a: a restraining influence: check "kept a tight ~ on the proceedings" b: controlling or guiding power--usu. used in pl. "the ~s of government"
3: opportunity for unhampered activity or use "gave full ~ to her imagination"
[2]rein vt (15c) 1: to control or direct with or as if with reins
2: to check or stop by or as if by a pull at the reins "~ed in her horse" "couldn't ~ his impatience" ~ vi 1 archaic: to submit to the use of reins
2: to stop or slow up one's horse or oneself by or as if by pulling the reins