reference line

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

deployment line; line of deployment (LD); line of departure

observer-target line (OT line)

scheme trail line (tag line)

grid reference box

grid reference system

guidance reference system

gyroscopic reference unit (GRU)

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

real reference point

muzzle reference system (MRS)

call for fire using `snail` grid reference

principal currency / reference currency

inertial reference system

strapdown attitude heading reference system

strapdown inertial reference system