What is a “junk” folder vs “spam” folder?

The junk folder and spam folder are functionally identical. They hold messages that the filter deemed unwanted but did not reject outright. The difference is purely naming convention.

Microsoft Outlook and Outlook.com call it the Junk Email folder. Gmail calls it Spam. Yahoo Mail uses Spam. Apple Mail uses Junk. The underlying function is the same: a quarantine area for suspicious messages.

Messages in this folder are typically held for a limited time (often 30 days) before automatic deletion. Users can rescue legitimate messages by moving them to the inbox, which also signals the filter to adjust its judgment for that sender.

Different harbors, different signage, same holding dock for suspicious cargo.