subject
noun
- 1a person or thing that is being discussed, described, or dealt with: I’ve said all there is to be said on the subject he’s the subject of a major new biography
- a person or circumstance giving rise to a specified feeling, response, or action: the incident was the subject of international condemnation
- a person who is the focus of scientific or medical attention or experiment: subjects were asked to complete a questionnaire
- Logic the part of a proposition about which a statement is made.
- Music a theme of a fugue or of a piece in sonata form; a leading phrase or motif: the chorale-like second subject of the Scherzo
- 2a branch of knowledge studied or taught in a school, college, or university: maths is not my best subject
- 3a member of a state other than its ruler, especially one owing allegiance to a monarch or other supreme ruler: the legislation is applicable only to British subjects
adjective
adverb
verb

Origin:
Middle English (in the sense '(person) owing obedience'): from Old French suget, from Latin subjectus 'brought under', past participle of subicere, from sub- 'under' + jacere 'throw'. Senses relating to philosophy, logic, and grammar are derived ultimately from Aristotle's use of to hupokeimenon meaning 'material from which things are made' and 'subject of attributes and predicates'

Grammar
In a statement clause, the subject: comes at or near the beginning of the clause comes before the verb agrees with the verb in number and person often denotes the doer of an action.It also often gives a clear idea of what the sentence is about. The subject can be: a noun: Yoga is religious. a verbal noun: Dancing is a wonderful way of keeping in training. an infinitive: To err is human. a pronoun: They argued ferociously about Ireland. a noun phrase: The core of the problem is simple. a noun clause: What he said was true.