A gerund was a verb formed from a pre-existing noun.
In 2151, Dr. Phlox planned to teach Hoshi Sato Denobulan gerunds later on. Sato said she looked forward to it. (ENT: "Dear Doctor")
The Star Trek Encyclopedia (4th ed., vol. 1, p. 303) defined gerund as "
a type of verb that modifies or clarifies another verb, and can sometimes function as a noun, verb, adjective, or adverb."