Devices running versions 2.0 and higher of the Android mobile operating system include a feature called "combined inbox." The pre-installed, default email client app allows you pull incoming email messages off multiple POP, IMAP and Exchange accounts. Combined inbox then lists all messages as part of the same inbox view. You can, for any configured email account, choose to see the messages arrived to that account on their own separate inbox -- not as part of the combined inbox.
Press the "Home" button on the Android device. The device will display its home screen.
Drag the tab at the edge of the screen over the rest of the screen. The device will display a list of all apps installed. Scroll until you see the app named "Email."
Press the "Menu" button on the device, then select "Accounts." Tap on the account whose emails you want to see separate from other accounts'. The email client app will display a separate inbox containing only those messages.