A gerund is a verbal noun formed with an "-ing" ending that can serve several grammatical functions in a sentence. It can be the subject, direct object, object of a preposition, subjective complement after a linking verb, or appositive renaming another noun. Examples are given of gerunds functioning as subjects ("Hunting tigers is dangerous"), direct objects ("I enjoy cooking"), objects of prepositions ("By reading, we can explore"), subjective complements ("One of my favorite chores is cleaning"), and appositives ("Psychology, studying the human mind, has become popular").