IPA: //ˌsʌbˈdɪsɪplɪn//
KK: /sʌbˈdɪsəplɪn/
A specific area of study that is part of a larger field of knowledge.
Biochemistry is a subdiscipline of biology that focuses on the chemical processes within living organisms.
Subdiscipline → It is formed from "sub-" (meaning under or below) and "discipline" (from Latin "disciplina", meaning instruction or training). The word refers to a specialized field of study that exists under a broader discipline.
Think of a field of study that is 'under' ('sub-') a larger area of knowledge, which is what a subdiscipline represents.