'Reins of a vault' definitions:

Definition of 'Reins of a vault'

From: GCIDE

Reins \Reins\ (r[=a]nz), n. pl. [F. rein, pl. reins, fr. L. ren, pl. renes.]
1. The kidneys; also, the region of the kidneys; the loins. [1913 Webster]
2. The inward impulses; the affections and passions; -- so called because formerly supposed to have their seat in the part of the body where the kidneys are. [1913 Webster]
My reins rejoice, when thy lips speak right things. --Prov. xxiii. 16. [1913 Webster]
I am he which searcheth the reins and hearts. --Rev. ii. 23. [1913 Webster]
Reins of a vault (Arch.), the parts between the crown and the spring or abutment, including, and having especial reference to, the loading or filling behind the shell of the vault. The reins are to a vault nearly what the haunches are to an arch, and when a vault gives way by thrusting outward, it is because its reins are not sufficiently filled up. [1913 Webster]