In the beginning was the Word.  Or in our case, the Unit.  The
fundamental unit of electricity is the coulomb, which is a certain
number of electrons.  A large number, around 6.02x10^23.  It
undoubtedly has some fancy-schmancy definition now, but it was
originally defined in France as the number of electrons that would
plate some miniscule quantity of pure silver onto an electrode.  So
it is the unit of quantity.  The rest come from it.  Note: you will
see circular definitions below.  The interested may chase them down,
but it's not necessary to do that to use them.

The Ampere is the unit of rate of flow. The flow of one Coulomb per
second is one Ampere.

The Volt is the unit of pressure, or more formally electromotive
force.  One Volt will cause a flow of one Ampere through a resistance
of one Ohm.

The Ohm is the unit of resistance to flow.  One Ohm will allow one
Ampere to flow under a pressure of one Volt.

The Watt is the unit of power, or rate of work. One Ampere flowing
through one Ohm will develop one Watt.

The total amount of work is the product of rate and time, so one Watt
for one Second will do one Watt-Second of work.  Similarly the Watt-hour.

  --
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'89 Po' White Star "Scamp"