It's actually part of the present participle form of verbs. Here's how it works:
* Present Participle: This is a verb form that acts as a verb (it shows an action) and an adjective (it describes something).
* Formation: The present participle is typically formed by adding -ing to the base form of the verb.
* Examples:
* Singing: The bird is singing. (verb)
* A singing bird: (adjective)
* Running: She is running a marathon. (verb)
* A running track: (adjective)
In short, "-ing" doesn't have a separate meaning. It's part of the present participle, which indicates ongoing action or a descriptive quality.