Auto/ˈɔːtəʊ/ Definition 1 of 4Pro Tip 1/3Primary Usage Mainly used for personal transportation, not for heavy loads or public transit. I'll take my auto to work today. Pro Tip 2/3Colloquial Context 'Auto' in conversation often refers to private cars, less common in formal writing. Do you want to see my new auto? Pro Tip 3/3Cultural Nuance More common in U.S. English; other regions might use 'car' more frequently. My uncle collects vintage autos.