^ Know that normal is
1: perpendicular ; especially : perpendicular to a tangent at a point of tangency
2 a: according with, constituting, or not deviating from a norm, rule, or principle b: conforming to a type, standard, or regular pattern
3: occurring naturally <normal immunity>
4 a: of, relating to, or characterized by average intelligence or development b: free from mental disorder : sane
5 aof a solution : having a concentration of one gram equivalent of solute per liter b: containing neither basic hydroxyl nor acid hydrogen <normal silver phosphate> c: not associated <normal molecules> d: having a straight-chain structure <normal butyl alcohol>
6of a subgroup : having the property that every coset produced by operating on the left by a given element is equal to the coset produced by operating on the right by the same element
7: relating to, involving, or being a normal curve or normal distribution <normal approximation to the binomial distribution>
8of a matrix : having the property of commutativity under multiplication by the transpose of the matrix each of whose elements is a conjugate complex number with respect to the corresponding element of the given matrix