The study or theory of knowledge is called-

• The study or theory of knowledge is called "Epistemology".• Epistemology (Noun)- English Meaning: The study or theory of knowledge, especially with regard to its methods, validity, and scope, and the distinction between justified belief and opinion.- Bangla Meaning: জ্ঞানতত্ত্ব। • Other options:ক) Psychology:- English Meaning: The science of mind and behavior.- Bangla Meaning: মনোবিদ্যা; মনোবিজ্ঞান।গ) Etymology:- English Meaning: The study of the origin and history of words, or a study of this type relating to one word.- Bangla Meaning: শব্দের উৎপত্তি ও ইতিহাসসংক্রান্ত বিজ্ঞান। ঘ) Philology:- English Meaning: The study of language; the branch of knowledge that deals with the structure, historical development, and relationships of a language or languages.- Bangla Meaning: ভাষাবিজ্ঞান; ভাষাতত্ত্ব। Source:1. Oxford Dictionary.2. Merriam-Webster Dictionary.