What does the root word later mean?

The root word "later" doesn't actually exist as a standalone root word. It's actually the comparative form of the adjective "late."

Here's how it breaks down:

* Late: meaning "occurring or done after the usual or expected time"

* Later: meaning "happening or done at a time that is after something else"

So, while there isn't a root word "later," it's derived from the root word "late," which can be traced back to Old English and ultimately to Proto-Germanic.