1580s, "pertaining to a place;" see topic + -al (1). Medical sense "applied to a particular part of the body" is from c. 1600. Meaning "of or pertaining to topics of the day" is from 1873. Related: Topically.
1630s, "a class of considerations from which probable arguments can be drawn," singular form of "Topics" (1560s), the name of a work by Aristotle on logical and rhetorical generalities, from Latin Topica, from Greek Ta Topika, literally "matters concerning topoi," "commonplaces," neuter plural of noun use of topikos "pertaining to a common place, of a place, local," from topos "place" (see topos). The meaning "matter treated in speech or writing, subject, theme" is first recorded 1720.