A Google account can show several sessions for one phone or computer. A browser, an app, or a fresh sign-in can each create an entry. Seeing the same device name twice is worth reviewing, but it does not prove that somebody has broken in.
1. Open the account yourself. From your Google Account, choose Security & sign-in, then Your devices and Manage all devices. Avoid a link in an unexpected warning message. Review the list while you have a device you trust and your normal sign-in methods available.
2. Read the details together. Look at the device, browser, approximate location, and activity time. Google says the displayed time can reflect background syncing. A nearby city can also appear instead of your exact location. Compare the entry with recent travel, a replacement phone, or a browser you used briefly.
3. Close access you no longer need. Sign out of a borrowed computer or a device you have sold. If several sessions share a device name and you cannot tell which belong to it, Google's guidance is to sign out of all sessions with that name. Expect to sign in again on any of your own affected devices.
4. Escalate unfamiliar activity. Review Recent security events and use the option to flag activity that was not yours. If you think someone else is using the account, follow Google's compromised-account process and change the password. Review recovery information, two-step verification, and apps with account access. In Gmail, check for forwarding rules or filters you did not create.
A session review is a useful cleanup step, not a complete incident investigation. It cannot establish whether someone already copied information. If you cannot sign in, use Google's official account recovery flow. If the account is managed by a school or employer, involve its support team rather than changing organization-wide settings.