topicyoudaoicibaDictYouDict[topic 词源字典]
topic: [16] Greek tópos meant ‘place’. From it was derived the adjective topikós ‘of a place’, which came to mean ‘commonplace’. Aristotle used it in the title of his treatise Tà topiká, which contains commonplace arguments, and it was with direct reference to this that the word first arrived in English (via Latin topica). The sense ‘subject, theme’ arose in the 18th century from the notion of the various heads of argument contained in Tà topiká and works like it.

The derived topical [16] originally meant ‘of topics’; the specialization to ‘of topics of the day, of current interest’ is as recent as the second half of the 19th century. The word’s original notion of ‘place’ is preserved in topography [15] and topology [17]. The diminutive form of Greek tópos was tópion ‘small place’, hence ‘field’.

Latin took over its plural as topia, and used it for ‘ornamental gardening’. From it was derived the adjective topiārius, which forms the basis of English topiary [16].
=> topiary, topography[topic etymology, topic origin, 英语词源]
topic (n.)youdaoicibaDictYouDict
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.