/ ˈtɒpɪk; NAmE ˈtɑːp-/ noun
a subject that you talk, write or learn about :
The main topic of conversation was Tom's new girlfriend.
The article covered a wide range of topics.
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WORD ORIGIN
late 15th cent. (originally denoting a set or book of general rules or ideas): from Latin topica , from Greek ta topika , literally matters concerning commonplaces (the title of a written work by Aristotle), from topos a place.