Normal (geometry) Normal (geometry) In geometry, a normal is an object such as a line or vector that is perpendicular to a given object. For example, in two dimensions, the normal line to a curve at a given point is the line perpendicular to the tangent line to the curve at the point. In three dimensions, a surface normal, or simply normal, to a surface at a point "P" is a vector that is perpendicular to the tangent plane to that surface at "P". The word "normal" is also used as an adjective: a line normal to a plane, the normal component
All that glitters is not gold Portia's boxes (Act II - Scene VII - Prince of Morocco): Panning for gold often results in finding pyrite, nicknamed fool's gold, which reflects substantially more light than authentic gold does. Gold in its raw form appears dull and lusterless. The original version of the saying used the word "glisters", but "glitters" long ago became the predominant form. Poet John Dryden used "glitter" in his 1687 poem "The Hind and the Panther". The words "glister" and "glitter" have the same meaning. In pop culture, this phrase shows up in Bob Marley's "Get Up, Stand Up". It is also used as