Ford Motor Co., the second-largest U.S. automaker, and Toyota Motor Corp., Asia's biggest car company, are each saying they produced the best-selling car in the world in the first half. Their definitions are the key.

The Ford Focus was the world's top-selling "single-car nameplate" — a vehicle sold under only one name — with 489,616 sold in the first six months of 2012, topping the Corolla's 462,187, Ford said in statement that cited researcher IHS Automotive.

Toyota said its first-half Corolla sales total is 603,840, including Corolla derivatives such as the Matrix wagon sold in the U.S.