definition of
rein in

[1] #1 rein in 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". wn

[2] #2 rein in v. control and direct with or as if by reins; "rein a horse". wn

[3] #3 rein in 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". wn