sociological adj.

"the science of social phenomena; the study of the structure and development of human societies," 1842, from French sociologie, a hybrid coined 1830 by French philosopher Isidore Auguste Comte (1798-1857), from Latin socius "associate" (see social (adj.)) + Greek-derived suffix -logie (see -logy).

compound adjectival word-forming element, usually interchangeable with -ic but sometimes with specialized sense (such as historic/historical, politic/political), Middle English, from Late Latin -icalis, from Latin -icus + -alis (see -al (1)). Probably it was needed because the forms in -ic often took on a noun sense (for example physic). Forms in -ical tend to be attested earlier in English than their twins in -ic.