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"
control and direct with or as if by reins;
"rein a horse"
stop or check by or as if by a pull at the reins;
"He reined in his horses in front of the post office"
- The prisoners must be kept in check.
- rein in 严加控制