definition
strict definition
pyramid
A roof with three or four sloping sides meeting at a single point, sometimes classified as a spire when very tall and narrow.
A pyramidal roof has 3 or (more often) 4 sloping sides, all of which meet in a single point. If the height of such a roof vastly exceeds its width, it may be classified as a spire.
The meeting point distinguishes the form from a hipped roof, whose sides meet along a ridge.
A cone-like tapered roof has more than four sides or a curved plan. The pyramidal form retains the three-or-four-side condition.