The seven fundamental metric units and the quantities they measure are:

• the kilogram [kg], which mesures weight.
• the metre [m], which measures length.
• the second [s], which measures time.
• the ampere [A], which measures current.
• the degree [$^\circ$] (Kelvin or Celcius), which measures temperature.
• the mole, which mesures number of atoms.
• the candela, which measures light intensity.

The metre is defined as the distance traveled by light in a given fraction of a second.

The metric energy unit known as the joule is defined as

The luminosity of light, or candela, is measured in terms of power, designated in watts, or joules per second.

http://www.wired.com/magazine/2011/09/ff_kilogram/all/1