an upright shaft or structure, of stone, brick, or other material, relatively slender in proportion to its height, and of any shape in section, used as a building support, or standing alone, as for a monument

Gothic pillars; a pillar to commemorate Columbus.

a natural formation resembling such a construction

a pillar of rock; a pillar of smoke.

any upright, supporting part; post

the pillar of a table.

a person who is a chief supporter of a society, state, institution, etc.

a pillar of the community.

Horology . any of several short parts for spacing and keeping in the proper relative positions two plates holding the bearings of a watch or clock movement.

Mining . an isolated mass of rock or ore in a mine, usually serving as a roof support in early operations and later removed, wholly or in part.

Nautical . mast 1 ( def. 2 ) .

to provide or support with pillars. ?

from pillar to post

aimlessly from place to place.

uneasily from one bad situation or predicament to another.

noun

colonnade , mast , obelisk , pedestal , pier , pilaster , piling , post , prop , shaft , stanchion , support , tower , upright , backbone * , guider , leader , light * , rock * , sinew , supporter , tower of strength , upholder , worthy , anta , column , mainstay , maintainer , monolith , pile , stele