Normal

a. [Lat. normalis, from norma, rule, pattern; Fr. & Sp. normal, It. normale.] 1. According to an established norm, rule, or principle; conformed to a type or regular form; accomplishing the end or destiny; performing the proper functions; not abnormal; regular; analogical. The deviations from the normal type or decasyllable line would not justify us in concluding that it [rhythmical cadence] was disregarded. Hallam. 2. (Geom.) According to a square or rule; perpendicular; forming a right angle. Normal group (Geol.), a group of rocks taken as a standard. Lyell.—Normal school, a school whose methods of instruction are to serve as a model for imitation; an institution for the education of teachers. Syn.—Regular; ordinary; analogical.—NORMAL, REGULAR, ORDINARY. Regular and ordinary are popular terms of well-known signification; normal has now a more specific sense, arising out of its use in science. A thing is normal, or in its normal state, when strictly conformed to those principles of its constitution which mark its species. It is abnormal when it departs from those principles.