A gerund (or verbal noun) is a noun form using present participle verbs ending in -ing (which are also adjectives). Some examples are swimming, running, washing, cooking, dancing, etc.
I think you are asking what the name is for verbs acting as nouns. They are called gerunds and usually if not always end in -ing. Running is good exercise but hard on the feet and knees. To run is a...
A verb functioning as a noun is called a gerund. Here is an example of a gerund: Swimming is my favorite sport. In this sentence, swimming is the gerund. It ordinarily acts as the present tense of...