Enhanced flight vision system
Enhanced flight vision system (EFVS) means an electronic means to provide a display of the forward external scene topography (the natural or manmade features of a place or region especially in a way to show their relative positions and elevation) through the use of imaging sensors, such as a forward looking infrared, millimeter wave radiometry, millimeter wave radar, low light level image intensifying.
Source
14 CFR § 1.1
Scoping language
As used in Subchapters A through K of this chapter, unless the context requires otherwise: