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 is gold does not glitter All that is gold does not glitter "All That is Gold Does Not Glitter" (alternatively known as "The Riddle of Strider" or "Song of Aragorn") is a poem written by J. R. R. Tolkien for his fantasy novel "The Lord of the Rings". It alludes to an integral part of the plot that describes Aragorn, son of Arathorn. The poem appears twice in "The Fellowship of the Ring", the first volume of "The Lord of the Rings". It appears first in Chapter Ten, "Strider", in Gandalf's letter to Frodo Baggins in Bree, although when Frodo reads it he does not