GEOLOGY

Detailed explanation-1: -OK, ologist itself isn’t an actual word; rather it’s a root word, which stems from ology, meaning “any science or branch of knowledge.” When you add various combining forms to ologist, you get terms that refer to the people who are experts in a particular science or branch of knowledge.

Detailed explanation-2: -The suffix ology is commonly used in the English language to denote a field of study.

Detailed explanation-3: -The English-logy suffix originates with loanwords from the Greek, usually via Latin and French, where the suffix (-) is an integral part of the word loaned. E.g. astrology from astrologia, since the 16th century. The French-logie is a continuation of Latin-logia, ultimately from Ancient Greek- (-logía).

Detailed explanation-4: -[Gr. logos, word, reason] Suffix meaning science or study of.