Toyota asked Americans for the plural of Prius, and they chose Prii
In February 2011, Toyota's American arm let the public vote on the plural of Prius. The options were Prien, Prii, Prium, Prius and Priuses, and "Prii" won. The strictly correct Latin answer, priora, was unavailable anyway, since Lada had already used it for a car in 2007. Most English speakers still just say Priuses.
The name itself is Latin for first or original, and it fit. When the Prius went on sale in Japan on 10 December 1997, it became the first mass-produced petrol-electric hybrid car in the world. Styled by designers in California who beat rival Toyota studios, it won Car of the Year Japan in its launch year. Only 37,425 of that original model were built, and Toyota executives later admitted the company lost money on every one.
The second version, from 2000, was the first sold outside Japan, gaining power to suit the longer, faster drives typical in America, where it listed at US$19,995. With it, Toyota finally broke even. The 2003 redesign turned the car into the familiar liftback, with a slippery drag coefficient of 0.26, an all-electric air-conditioning compressor that was an industry first, and some 530 patents behind it. Regulators in 2007 placed it among the cleanest cars on sale in the United States.
Later versions kept refining the idea. The third generation, from 2009, added electric-only, economy and power driving modes, offered an optional solar roof panel to help cool the cabin, and used bioplastics made from kenaf, a hibiscus relative, and ramie, a nettle. That model repeated the original's national award win. The fourth, from 2015, moved to a new modular platform and later gained all-wheel drive.
Sales climbed with each generation. By January 2017 the Prius family, which grew to include an MPV, a small hatchback and a plug-in, had sold 6.1 million units, 61 percent of all Toyota hybrids. A 2019 study ranked it the second longest-kept vehicle among American drivers.
Source: Toyota Prius
