The term 'Unit of Power' can be defined by several different solutions. A watt (4 letters) is a unit of power equal to one joule per second. A milliwatt (9 letters) is one thousandth of a watt. A kilowatt (8 letters) is one thousand watts. A megaton (7 letters) is a unit of energy equal to one million tons of TNT. A volt (4 letters) is a unit of electrical potential difference or electromotive force. A dyne (4 letters) is a unit of force equal to the force that imparts an acceleration of one centimeter per second squared to a mass of one gram. Lastly, a WHILE (5 letters) is a unit of power equal to one joule per second.