one half thickness rule

all for one and one for all / one for all and all for one

half colonel / half-bird

half-and-half bearing

armor plate thickness

armor thickness

partial-thickness crack

relative thickness of an aerofoil section

Reynolds number for boundary layer thickness

boundary layer thickness

displacement thickness of a boundary layer

energy thickness of a boundary layer

momentum thickness of a boundary layer

thickness

thickness of a aerofoil ratio

thickness of a shock wave

thickness of an aerofoil section

thickness of laminar sublayer

thickness of tooth

one-way UAV / one-way attack UAV (OWA UAV)

rule of law

slide rule

strong-arm rule

aiming rule operator

aiming rule

alidade rule

gun rule

decision rule

Prandtl-Glauert rule

rule

rule-making

nautical slide rule

parallel rule(r)