Plain English Meaning

Ground or objects sticking up from it that an airplane could hit if it gets too low or off course.

Full Definition

Ground features such as mountains, ridges, hills, cliffs, towers, antennas, or man-made obstacles that pose a collision risk to an aircraft if it descends below a safe altitude or strays from a protected flight path. In instrument approach design, hazardous terrain is the terrain and obstacles the published procedure is built to keep the aircraft clear of.

Context Anchor

Seen in instrument approach and RNAV/GPS approach discussions, especially where terrain affects how the approach must be flown.