normal,
adj. 1a. perpendicular to a given line or plane, or to the tangent to a curve or surface at the point of contact. For example, in the figure below, the bold line PN is normal to the curve at the point P, where its tangent is the line PT.
NP is normal to the curve.
b. (as substantive) a line drawn normal to another line, plane, curve or surface. The normal to a surface expressed as F(x, y, z)=0, is given by the gradient vector ∇F(x, y, z). 2. see principal normal. 3. see normal topological space, normal subgroup. 4. (of a set of functions) precompact with respect to the topology induced by the Chebyshev norm. 5. another term for normally distributed. 6. (of a property) usual, desirable, regular.
b. (as substantive) a line drawn normal to another line, plane, curve or surface. The normal to a surface expressed as F(x, y, z)=0, is given by the gradient vector ∇F(x, y, z). 2. see principal normal. 3. see normal topological space, normal subgroup. 4. (of a set of functions) precompact with respect to the topology induced by the Chebyshev norm. 5. another term for normally distributed. 6. (of a property) usual, desirable, regular.