Definition - What does Nroff mean?
Nroff is a descendant of RUNOFF or roff.
Techopedia explains Nroff
A command, which must be located to the far left of a document, is placed directly above the line of applied text. Nroff only recognizes the period as the beginning of a command if the period is in this location.
Commands are easy to remember and use because they are often acronyms or command shortcuts, such as .bp (break point) and .in 3 (indent by 3 spaces). This type of document formatting is known as nroffing.