Google's Android operating system is used on hundreds of smartphones and tablets. But the flagship Android devices, the ones the company calls "the best of Google," are labeled Nexus. They are meant to show the world all that an Android device can be, and are designed and sold directly online by Google. Next week, the company will begin offering the latest phone in this line, the Nexus 4.

This new phone is part of a Google-designed portfolio that now includes two other devices: the Nexus 7 and Nexus 10 tablets. The phone,...