[n] one of a pair of long straps (usually connected to the bit or the headpiece) used to control a horse
[n] any means of control; "he took up the reins of government"
[v] keep in check; "rule one's temper"
[v] stop or check by or as if by a pull at the reins; "He reined in his horses in front of the post office"
[v] stop or slow up one's horse or oneself by or as if by pulling the reins; "They reined in in front of the post office"
[v] control and direct with or as if by reins; as of a horse