Pillar Fr. piler, Mod. pilier, Late Lat. pilare, from pi/a, column), an isolated upright structure, of narrow width in relation to its height, which is either employed as a support for a superincumbent load of some sort or is set up for commemorative or ornamental purposes. In the first sense the word has many common applications, as to columns supporting the girders of a warehouse floor or the deckbeams of a ship, to the single central support or pedestal of a table, machine-tool, &c., and to the masses of coal which the miner leaves in certain methods of working as supports to the roof (see Coal); it is also used figuratively of persons in such phrases as a "pillar of the state." In architecture it has strictly the second sense. The column erected in honour of Diocletian at Alexandria is known as Pompey's pillar, and the so-called columns of Trajan and Antoninus are in reality pillars, performing no structural function beyond that of carrying a statue. In India the only example is the iron pillar at Delhi, which is an extraordinary specimen of the ironworker's art considering the remote date at which it was made. Up to the middle of the 19th century the term "pillar" was employed to designate the masses of masonry in a church, which carry the arcades, but now the term "pier" is invariably adopted in preference.