Толковый словарь английского языка Oxford English Reference - useful

adj. 1 a of use; serviceable. b producing or able to produce good results (gave me some useful hints). 2 colloq. highly creditable or efficient (a useful performance). Phrases and idioms make oneself useful perform useful services. useful load the load carried by an aircraft etc. in addition to its own weight. Derivatives usefully adv. usefulness n.