Tesla, the electric car company, was named after Nikola Tesla, the Serbian-American inventor of alternating current (AC).
Engineers Martin Eberhard and Marc Tarpenning chose to name their electric car company “Tesla Motors” after the inventor because of his pioneering work with electricity. Tesla famously competed with Thomas Edison, the proponant for direct current (DC), in the War of the Currents, a race to produce the best electrical transmission system in the 1880s. His other inventions included the Tesla Coil (1891) and one of the first wireless remote controls (1898).
Elon Musk, who took over as CEO in 2008, revealed the company had to purchase the name: "We didn’t actually come up with the Tesla Motors name. Bought trademark off Brad Siewert for $75k in late 2004. He’d originally filed for it in 1994. Our alternative name was Faraday, which was used by a competitor several years later."
Source: Nikola Tesla