nroff (short for "new roff") is a Unix text-formatting program. It produces output suitable for simple fixed-width printers and terminal windows. It is an integral part of the Unix help system, being used to format man pages for display.
nroff was written by Joe Ossanna for Version 2 Unix, in Assembly language and then ported to C.
It was a descendant of the RUNOFF program from CTSS, the first computerized text-formatting program, and is a predecessor of the Unix troff document processing system.
There is also a free software version of nroff in the groff package.