The watt (pron.: /ˈwɒt/WOT; symbol: W) is a derived unit of power in the International System of Units (SI), named after the Scottish engineer James Watt (1736–1819). The unit, defined as one joule per second, measures the rate of energy conversion or transfer.
The volt (symbol: V) is the SIderived unit for electric potential (voltage), electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta (1745–1827), who invented the voltaic pile, possibly the first chemical battery.