1A loanword meaning 'car'. It is rarely used on its own to mean 'a car' in real Japanese — 車 is used for that instead. カー mainly appears as a combining form in compounds like マイカー (one's own car), カーナビ (car navigation), and カーレース (car race).
毎日マイカーで会社に通っている。
I commute to work by my own car every day.
最新のカーナビを取り付けたら、道に迷わなくなった。
After installing the latest car navigation system, I stopped getting lost.
週末は友達とカーレースを観戦しに行った。
On the weekend, I went to watch a car race with friends.
カー用品店で新しいタイヤを買った。
I bought new tires at a car accessories shop.