What is a gerund?
The term gerund refers to the “-ing” form of a verb (e.g., “walking”) when it plays the role of a noun.
For example, in the sentence “walking is a hobby of mine,” “walking” plays the role of a subject. It could be replaced by another noun like “chess” to create a similar statement. So you can see that although the gerund looks like a verb, it behaves like a noun.
Gerunds are distinguished from present participles, which look the same but are used as adjectives (e.g., “the walking man”) or to form continuous verb tenses (e.g., “I had been walking that morning”).