A participle is a form of a verb that can function as an adjective. A present participle ends in "-ing" (e.g. running), while a past participle can end in "-ed," "-en," "-d," "-t," "-n," or "-ne" (e.g. walked, eaten). A gerund is a noun form of a verb ending in "-ing" that functions as a noun in a sentence (e.g. Swimming is my favorite hobby).