Toyota is the name of the Japanese car company, and by extension a car made by it — 'he drives a Toyota', 'we sold the old Toyota'. Notice that second use: the brand name works as an ordinary countable noun for the vehicle, so you can say a Toyota, two Toyotas, my Toyota. It always keeps its capital letter, because it is still a name. The company is one of the largest carmakers in the world, and the reputation attached to the word matters for understanding how people use it: Toyota is a byword for reliability rather than luxury or excitement, so 'it's a Toyota' often carries the sense 'it is not glamorous, but it will keep working'. Taiwanese students should know that although Toyota cars here are sold and made through Hotai and Kuozui, the word people say is still 豐田 or simply Toyota. Two production ideas also carry the name in business English — the Toyota Production System and 'just-in-time' manufacturing — so you may meet Toyota in a business class with no cars in sight.