The pattern of metal, silkscreen, soldermask relief, and drills which
defines where you place a component on a circuit board.
Footprints are the placed by the user onto the PC board during the
placement phase of PCB layout.
Gerber File
The file format used in the industry to convey a board database to the
manufacturer is RS-274-X (which replaces the now obsolete RS-274-D
format). This file format was originally developed by Gerber for
their photo plotters and thus RS-274-D and RS-274-X format files
are often times refered to as “Gerber” files.