Rh

Rh
One of the rarest metals on earth.
rhenium
A rare element that is a silvery coloured metal which resists corrosion and oxidation but slowly tarnishes in moist air.
Rheology
Study of flow characteristics
Rheostat
A device to regulate the flow of electric current by transforming part or all of it into heat.
rho
A letter of the Greek alphabet.
Rhodium
One of the rarest metals on earth.
Rhombic Antenna
A diamond-shaped antenna used widely for long-distance, high-frequency transmission and reception.
Rhombus
A parallelogram with four equal sides.
Rhyolite
Volcanic rock that characteristically is light in colour, contains 69% silica or more, and is rich in potassium and sodium.