Dyne:
the force required to accelerate 1 g of mass at 1 cm per second; 1 dyne = 10^{- 5} newtons

Energy:
the ability or capacity to do work; in physics, essentially synonymous with work

Energy density:
energy per unit area; in lasers, units = joules/cm²

Erg:
a dyne-centimeter; the work or energy of 1 dyne applied over a distance of 1 cm; a unit of energy; 1 erg = 10^{- 7} joules

Joule:
a newton-meter; the work or energy of 1 newton applied over a distance of 1 meter; a unit of energy; 1 joule = 10⁷ ergs

Nanosecond:
a billionth (10^{- 9}) of a second

Newton:
the force needed to accelerate 1 kg of mass at 1 meter per second per second; 1 newton = 10⁵ dynes

Picosecond:
a trillionth (10^{- 12}) of a second

Power:
energy per unit of time; how fast energy is produced or transferred

Power density:
power per unit area; in lasers, units = watts/cm²

Watt:
one joule per second; a unit of power

Work:
“force times distance”; the product of a force and the distance through which it produces displacement; synonymous with energy