later
At a time after now or after something else happens.
Later means at a time after the present moment or after another event. When your friend says “see you later,” they mean they'll see you at some point in the future, though exactly when might not be specified. If you tell your mom you'll clean your room later, you're promising to do it after whatever you're doing now.
The word works across different time scales. “Later today” might mean in a few hours, while “later in life” could mean years from now. A history book might explain that Rome fell and later the Renaissance began, spanning centuries between those events.
Later can also mean more recent or further along in a sequence. The later chapters of a book come after the earlier ones. A musician's later albums are the ones they recorded more recently in their career.
People sometimes use later casually as a goodbye, short for “see you later.” And when someone says “sooner or later,” they mean eventually, at some point in time, even if they don't know exactly when.