IPA: /ˌɛsəˈtɛrɪkə/
KK: /ˌɛsəˈtɛrɪkə/
Things that are intended for or likely to be understood by only a small number of people with specialized knowledge or interest.
The book delves into the esoterica of ancient philosophies that few people understand.
Esoterica is derived from the Greek word "esoterikos" (meaning inner or within), which comes from "esoteros" (meaning more within). The term refers to knowledge that is intended for or likely to be understood by only a small number of people, often relating to specialized or obscure subjects.
Think of 'inner' or 'within' to remember that esoterica refers to knowledge that is meant for a select few, not the general public.