A Topic

1. Subject; theme; a category or general area of interest.
2. (Internet) Discussion thread.
3. (music) A musical sign intended to suggest a particular style or genre.
4. (obsolete) An argument or reason.
5. (obsolete, medicine) An external local application or remedy, such as a plaster, a blister, etc.

Synonyms

• (area of interest): subject, subject area