Noun

(en noun)

Subject; theme; a category or general area of interest.

*{{quote-magazine, date=2013-08-03, volume=408, issue=8847, magazine=(The Economist)

, title= The machine of a new soul , passage=The yawning gap in neuroscientists’ understanding of their topic is in the intermediate scale of the brain’s anatomy. Science has a passable knowledge of how individual nerve cells, known as neurons, work. It also knows which visible lobes and ganglia of the brain do what. But how the neurons are organised in these lobes and ganglia remains obscure. Yet this is the level of organisation that does the actual thinking—and is, presumably, the seat of consciousness.}}

(Internet) Discussion thread.

(obsolete) An argument or reason.

* Bishop Wilkins

contumacious persons, who are not to be fixed by any principles, whom no topics can work upon

(obsolete, medicine) An external local application or remedy, such as a plaster, a blister, etc.

(Wiseman)

Noun

(en noun)

Someone involved in a discussion, especially a participant in a formal discussion or who has been assigned a particular role or topic.

* 2005 , Julie A. Cassiday, "Kirov and Death in The Great Citizen''," ''Slavic Review , vol. 64, no. 4, p. 799n:

I would like to thank Cynthia Ruder, whose comments as panel discussant helped me to rework my original paper.

*2012 , Faramerz Dabhoiwala, The Origins of Sex , Penguin 2013, p. 319:

*:The prominence given to readers' responses to topical issues [...] made concrete the sense of belonging to a large, active, and opinionated community of discussants .