corbel

A structural piece of stone, wood or metal jutting from a wall to carry a weight.

Corbelling, where rows of corbels gradually build a wall out from the vertical, has long been used as a simple kind of vaulting, for example in many Neolithic chambered cairns, where walls are gradually corbelled in until the opening can be spanned by a slab.

A very famous corbeled vault is at Newgrange:

corbelled-vault-at-newgrange Continue reading

caryatid

[ARCHITECTURE] a stone carving of a draped female figure, used as a pillar to support the entablature of a Greek or Greek-style building.

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I vaguely remembered this one from art history classes but good to be reminded!

In the centre stood the fountain, a shallow basin supported by a plinth of caryatids.

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Image source: Wikipedia