subpart
noun
sub·part
| \ ˈsəb-ˌpärt
\
\
variants:
or sub-part
plural subparts
or sub-parts
Definition of subpart
: something that is a part of a larger part
In language arts, the focus is placed on the parts and subparts of language, with the expectation that the learner will be able to put it all into a coherent whole after he or she has all the parts.— Betty Jo McCarty
especially
: a subordinate part of a legal document
according to the provisions of Subpart 4 … during an era that obviously pre-dated corporate legal departments, liability suits, OSHA rules, and subparts of parts of Federal Aviation Regulations … — Stephan Wilkinson