Normal

1. A straight line or plane drawn from any point of a curve or surface so as to be perpendicular to the curve or surface at that point.
2. Denoting a solution of such strength that every cubic centimeter contains the same number of milligrams of the element in question as the number of its molecular weight.
3. According to an established norm, rule, or principle; conformed to a type, standard, or regular form; performing the proper functions; not abnormal; regular; natural; analogical.
4. Standard; original; exact; typical.
5. Any perpendicular.
6. Denoting certain hypothetical compounds, as acids from which the real acids are obtained by dehydration; thus, normal sulphuric acid and normal nitric acid are respectively S(OH)6, and N(OH)5.
7. Denoting that series of hydrocarbons in which no carbon atom is united with more than two other carbon atoms; as, normal pentane, hexane, etc. Cf. Iso-.
8. According to a square or rule; perpendicular; forming a right angle. Specifically: Of or pertaining to a normal.