PYRAMID, the name for a class of buildings, first taken from a part of the structure,' and mistakenly applied to the whole of it by the Greeks, which has now so far acquired a more definite meaning in its geometrical sense, that it is desirable to employ it in that sense alone. A pyramid therefore should be under stood as meaning a building bounded by a polygonal base and plane triangular sides which meet in an apex. (For figures of geometrical pyramids see CRYSTALLOGRAPHY, and for their men suration see MENSURATION.) Such a form in architecture is best known in Middle Egypt, during the period from the IVth to the XIIth Dynasty (before 300o B.c.)—having square bases and angles of about 50°. In other countries various modifications of the tumulus, barrow or burial-heap have arisen which have come near to this type ; but these when formed of earth are usually circular, or if square have a flat top, and when built of stone are always in steps or terraces.
The origin of the pyramid type has been entirely explained by the discovery of the various stages of development of the tomb. In prehistoric times a square chamber was sunk in the ground, the dead placed in it, and a roof of poles and brushwood overlaid with sand covered the top. The Ist Dynasty kings developed a wooden lining to the chamber; then a wooden chamber free-standing in the pit, with a beam roof, then a stair way at the side to descend; then a pile of earth held in by a dwarf wall over it. By the IIIrd Dynasty this dwarf wall had 'The vertical height was named by the Egyptians pir-em-us (see E. Revillout, Rev. Eg., 2nd year, 305-309), hence the Greek form pyramis, pl. pyramides (Herod.), used unaltered in the English of Sandys (1615), from which the singular pyramid was formed.
expanded into a solid mass of brickwork, about 28o by 15o ft. and 33 ft. high. This was the mastaba type of tomb, with a long, sloping passage descending to the chamber far below it. This pile of brickwork was then copied in stonework early in the IIIrd Dynasty (Saqqara). It was then enlarged by repeated
heightening and successive coats of masonry. And lastly a smooth casing was put over the whole, and the first pyramid appeared (Medum).
The pyramids were each begun with a definite design for their size and arrangement ; this is plainly seen in the two largest, where continuous accretion (such as Lepsius and his followers propound) would be most likely to be met. Any section of these buildings shows how impossible it would have been for the passages to have belonged to a smaller structure (Petrie, 165). The supposition that the designs were enlarged so long as the builder's life permitted, was drawn from the compound mastabas of Saqqara and Medum; these are, however, quite distinct archi tecturally from true pyramids.
Around many of the pyramids peribolus walls may be seen, and it is probable that some enclosure originally existed around each of them. At the pyramids of Gizeh the temples attached to these mausolea may be still seen. As in the private tomb, the false door which represented the exit of the deceased person from this world, and towards which the offerings were made, was always on the west wall in the chamber, so the pyramid was placed on the west of the temple in which the deceased king was worshipped. The temple being entered from the east (as in the Jewish temples), the worshippers faced the west, looking towards the pyramid in which the king was buried.
The pyramid was never a family monument, but belonged— like all other Egyptian tombs—to one person, members of the royal family having sometimes lesser pyramids adjoining the king's (as at Khufu's) ; the essential idea of the sole use of a tomb was so strong that the hill of Gizeh is riddled with deep tomb-shafts for separate burials, often running side by side 6o or 8o ft. deep, with only a thin wall of rock between; and in one place a previous shaft has been partially blocked with masonry, so that a later shaft could be cut partly into it.