The word "adequate" refers to something that is sufficient or acceptable in quality or quantity for a particular purpose. It implies that something meets the necessary requirements or standards, but it may not exceed them. For instance, if a student has adequate preparation for an exam, it means they have studied enough to perform satisfactorily, but not necessarily to excel.
The word "adequate" comes from the Latin word "adaequatus," which is the past participle of "adaequāre," meaning "to make equal." The prefix "ad-" means "to" or "toward," and "aequus" means "equal." Thus, it literally implies being equal to or sufficient for a purpose.