from The Century Dictionary and Cyclopedia
- n. In architecture, a shaft, almost invariably engaged, rising from a floor or from the capital of a pier below, to receive the spring of a rib of a roof-vault; also, a shorter shaft engaged in the wall and rising from a corbel, from the top of which shaft the rib of the vault springs.
Sorry, no etymologies found.
 This term will be used wherever the usual term 'vaulting-shaft' is inapplicable.
The south wall is probably original, since (to mention one reason) part of the string-course upon it is worked on the same stone with the vaulting-shaft.
Between each of these lower arches is an enriched corbel of Purbeck marble, adorned with foliage in high relief, from which rises the vaulting-shaft, in a group of three, between the arches of the triforium to the base of the clerestory, having a capital of leafage, and from the top of which spring the ribs of the vaulting.
Unfortunately, however, as has been remarked, much of it has settled considerably, throwing the south-eastern angle altogether out of the perpendicular, one vaulting-shaft having in this manner been bent back and cracked in half.
"It may be readily noted," says the writer of a recent article on Winchester Cathedral, "how the new ashlar was brought down to the level of this vanished altar, and how Wykeham's vaulting-shaft has been made to end in foliation where it once rose in receipt of prayers and wax-candles vowed in return for mercies vouchsafed."
The vault-ribs were vigorously moulded and each made to spring from a distinct vaulting-shaft, of which three rested upon the cap of each of the massive piers below (Fig. 117).
Immediately above the carving, at the intersection of the main arches, is a corbelled head, from which rises a triple vaulting-shaft with foliated capitals, on a line with the base of the clerestory.