| Design Foundation | Rev 05 Sep 99 |

Glossary

paleography

parabola

(a) A kind of curve; one of the conic sections formed by the intersection of the surface of a cone with a plane parallel to one of its sides. It is a curve, any point of which is equally distant from a fixed point, called the focus, and a fixed straight line, called the directrix. See Focus. (b) One of a group of curves defined by the equation y = ax^{n} where n is a positive whole number or a positive fraction. For the cubical parabola n = 3; for the semicubical parabola n = 3/2. See under Cubical, and Semicubical. The parabolas have infinite branches, but no rectilineal asymptotes.

penumbra

n. 1. A partial shadow, as in an eclipse, between regions of complete shadow and complete illumination. 2. The grayish outer part of a sunspot. 3. An area in which something exists to a lesser or an uncertain degree. 4. An outlying, surrounding region; a periphery.

permutation

n. 1. A complete change; a transformation. 2. The act of altering a given set of objects in a group. 3. Mathematics An ordered arrangement of the elements of a set.

phonogram

pictogram

primary

progression

proportion