"The deer walked up to the man." 

Is the noun 'deer' singular or plural in the given sentence?

A part of speech that is used to name a person, place, animal, or thing is known as a noun. A noun is contained in almost every subject, and they can perform different roles in a sentence. In this sentence, 'deer' is used in the singular sense. Moreover, the word 'deer' is both singular and plural. Thus, the sentence "They saw two deer," is also grammatically correct.