relative speed

wind relative bearing / wind-relative bearing

supersonic speed (exceeds speed of sound / Mach 1)

variable-speed with speed control

instantaneous vertical speed indicator / instantaneous vertical-speed indicator (IVSI)

cruise speed / cruising speed

Nr gauge (Nr = speed of rotation) / rotor speed sensor

relative altitude

relative probability of adoption

relative strengths

relative velocity

relative inlet angle

relative outlet angle

relative bearing

relative equilibrium of a liquid

relative evaporation

relative roughness

relative thickness of an aerofoil section

relative density

relative humidity

movement and relative motion

relative isohyps / isohypse

Convention IV relative to the Protection of Civilian Persons in Time of War

Geneva Convention relative to the Protection of Civilian Persons in Time of War

relative wind

apparent speed

average speed

blade speed

convoy speed

critical speed

cross-country speed

endurance speed

exhaust speed