subtopic

subtopic

one of the divisions into which a main topic may be divided
Not to be confused with:subtitle – a secondary and usually explanatory title, as in a literary work

sub·top·ic

S0856000 (sŭb′tŏp′ĭk)n. One of the divisions into which a main topic may be divided.

subtopic

(ˌsʌbˈtɒpɪk) na subject which forms part of a larger topic