Tag

Tags are generally more granular than categories and do not have parent-child relationships by default. In practical terms, Tag belongs to the publishing and site-management layer. Knowing that layer is important because it tells you what the term can change, what it cannot change, and where to look when something behaves unexpectedly.

The common mistake is to use Tag as if it also meant Category. That blurs two separate decisions and usually sends troubleshooting in the wrong direction. A better test is practical: Avoid near-duplicate tags that fragment archives into many almost-empty term pages.

In day-to-day work, Tag matters when the concept needs to be identified precisely instead of being grouped with a nearby term. The practical value is not the vocabulary itself; it is being able to identify the right control, file, setting or decision when the concept becomes relevant.

Tags can connect posts around narrower concepts such as CSS Grid or accessibility even when the posts belong to different categories. That example is useful because it turns the definition into something you can recognize, test and discuss with other people working on the same project.

Use these references when you need documentation-level detail, specifications or product-specific behavior beyond the plain-English explanation above.