WordNet sense 1 (something regarded as a normative example):

convention, formula, pattern, rule

WordNet sense 2 (intersecting at or forming right angles):

perpendicular

WordNet sense 3 (conforming to a type):

typical

WordNet sense 4 (not deviating from what is normal):

regular

WordNet sense 5 (functioning or occurring in a normal way; lacking abnormalities or deficiencies):

natural

WordNet sense 6 (relating to or constituting the most frequent value in a distribution):

average

WordNet sense 7 (approximating the statistical norm or average or expected value):

mean