gyroscopic reference unit (GRU)

GRU special forces

Main Intelligence Directorate (GRU)

gyroscopic effect

gyroscopic gunsight

fixed ring (of a gyroscopic sight)

gyroscopic stabilizer

gyroscopic torque

attitude-and-heading reference system / attitude and heading reference system (AHRS)

battery coolant unit / battery-coolant unit (BCU)

gear reduction unit / gear-reduction unit

position and navigation unit / position navigation unit (PNU)

pinch (a unit) out of a large unit

grid reference box

grid reference system

guidance reference system

lay reference number

map reference

map reference code

military grid reference system (MGRS)

NATO Master Cross Reference List (NMCRL) (logistics)

numbered reference position system

reference

reference diversion point

reference data

reference number (order / message / report)

stabilization reference package (SRP)

target reference point (TRP)

terms of reference (TOR)

World Geographic Reference System (WGRS); georef

Army doctrine reference publication (ADRP)

reference azimuth

fictitious reference point