Answer:
The unit quantity of electricity in SI units is the coulomb (symbol C)
The ampere, in practice often shortened to amp, (symbol: A) is the unit of rate of electric charge transfer per second. The ampere is an SI base unit, and is named after André-Marie Ampère, one of the main discoverers of electromagnetism.
The volt (symbol: V) is the SI derived unit of electric potential difference or electromotive force. It is named in honor of the Lombard physicist Alessandro Volta (1745-1827), who invented the voltaic pile, the first chemical battery.
The ohm (symbol: Ω) is the SI unit of electrical impedance or, in the direct current case, electrical resistance, named after Georg Ohm.
NON-ELECTRIC UNITS
The joule is the SI unit of energy.
The watt (symbol: W) is the SI derived unit of energy transfer rate or power, equal to one joule of energy per second. It measures a rate of energy flow or energy conversion.
Additional Answer
In the United Kingdom, electricity companies charge their customers by the unit. The term 'unit' is short for the obsolete expression 'Board of Trade Unit' and is a measurement of electrical energy, equivalent to a kilowatt hour. So, 1 unit = 1 kW.h.