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
A-line (clothing) of flared skirt styles. "True" A-line shapes on the pattern of Dior and Saint Laurent saw a revival in the early 2000s. The A-line skirt has no visible embellishments for ease, such as pleats or slits, but is fitted to the upper hip by means of seams and/or darts. However, denim A-line skirts often have buttons down the center seam. Its fastening is usually kept discreet, with a side or back zipper. A belt is sometimes used. Pockets may be present, but not usually. It can be cut at any length. When referring to dresses and coats, the term "A-line"