The definition of useful is helpful or beneficial.
An example of useful used as an adjective is the phrase "useful information" which means information that is helpful.
that can be used to advantage; serviceable; helpful; beneficial; often, having practical utility
- Having a beneficial use; serviceable: a useful kitchen gadget.
- Being of practical use: a useful job; useful members of society.
- Prepositions: useful is used in useful for <purpose>, useful for <person> and useful to <person>. The words useful to are also found in construction such as It is useful to do, in which to marks an infinitive rather than being a preposition.
From use +"Ž -ful.