Subject may refer to: In knowledge and education An area of knowledge, a topic, an area of interest or study Course (education), a unit of academic instruction List of academic disciplines Subject (grammar), one of two main constituent parts of a sentence Subject case or nominative case, the grammatical case for a noun Subject term or index term, in information retrieval, a descriptor of a document used in bibliographic records Research subject, an organism (human or otherwise) that's observe… (More on Subject)