1the impression left by a foot or shoe on the ground or a surface.
the impact on the environment of human activity in terms of pollution, damage to ecosystems, and the depletion of natural resources:these countries are so populous that they can have a very big footprint
Computing the amount of memory or disk space required by a program.
2the area covered by something, in particular:
the area beneath an aircraft or a land vehicle which is affected by its noise or pressure.
the area in which a broadcast signal from a particular source can be received.
the space taken up on a surface by a piece of computer hardware.
footprint in other Oxford dictionaries
Definition of footprint in the US English dictionary