Rein \Rein\, v. t. [imp. & p. p. Reined (r?nd); p. pr. & vb. n. Reining.]

1. To govern or direct with the reins; as, to rein a horse one way or another.

He mounts and reins his horse. --Chapman.

2. To restrain; to control; to check.

Being once chafed, he can not Be reined again to temperance. --Shak.

To rein in or rein up, to check the speed of, or cause to stop, by drawing the reins.

Source: Webster's Revised Unabridged Dictionary (1913)