This document defines a gerund as a verbal ending in "-ing" that functions as a noun. Gerunds can serve as subjects, direct objects, subject complements, and objects of prepositions in sentences. Examples are provided that show gerunds functioning in each of these roles. The document also defines a gerund phrase as a group of words including a gerund and any modifiers, objects, or complements. Gerund phrases can serve as subjects, direct objects, and objects of prepositions.