What is gerund?

A gerund is a noun that is formed by adding (a gerund right there!) -ing to a verb. See example below.

A gerund is a verbal formed by adding ing to a verb. While it looks like the present participle, it functions as a noun, as in playing in We admired the young musician's tasteful playing.

It is a form of a verb when functioning as a noun, As writing in "writing is easy"

it means a language that is called Latin

As in Latin, a form regularly derived from a verb and functioning as a noun - as in Writing is easy In English a gerund is the "-ing" form of a verb when functioning as a noun, as "his profession is writing".