1 m. = 1 metre; 1 cm. = 1 centimetre = 0·394 inches.
1 μ = 1 micron = 1/1000 of a millimetre = 0·0001 cm. = 10⁻⁴ cm.
1 μμ = 1/1,000,000 of a millimetre = 10⁻⁷ cm.
1 cm.³ = 1 cubic centimetre.
1 g. = 1 gram; 1 kg. = 1 kilogram = 2·2 pounds.
1 kgm. = 1 kilogrammetre (the work or the energy required to lift 1 kg. 1 m.).
1 erg = 1·02 × 10⁻⁸ kgm. = 7·48 × 10⁻⁸ foot-pounds.
λ represents wave-length.
ν represents frequency (number of oscillations in 1 second).
ω represents frequency of rotation (number of rotations in 1 second).