Having a practical or beneficial use.
"The old map proved to be useful when we got lost in the foggy woods."
In plain English: Something useful is good for a specific purpose and helps you get things done.
"The new tool is very useful for fixing broken furniture."
Usage: Use useful to describe something that serves a practical purpose and provides benefit, such as saying the tool is very helpful for fixing leaks. Avoid confusing it with words like handy when you specifically need to emphasize tangible utility rather than mere convenience.
The word useful is formed by combining use with the suffix -ful. It entered English as a straightforward compound meaning something that can be used effectively.