| a. | 1. | Full of use, advantage, or profit; producing, or having power to produce, good; serviceable for any end or object; helpful toward advancing any purpose; beneficial; profitable; advantageous; |
| Adj. | 1. | useful - being of use or service; "the girl felt motherly and useful"; "a useful job"; "a useful member of society" Synonyms: utile Antonyms: useless - having no beneficial use or incapable of functioning usefully; "a kitchen full of useless gadgets"; "she is useless in an emergency" |
| 2. | useful - of great importance or use or service; "useful information"; "valuable advice" | |
| 3. | useful - capable of being turned to use or account; "useful applications of calculus" | |
| 4. | useful - having a useful function; "utilitarian steel tables" Synonyms: utilitarian |
USEFUL. That which may be put into beneficial practice.
2. The patent act of congress of July 4, 1836, sect. 6, in describing
the subjects of patents, mentions "new and useful art," and "new and useful
improvement." To entitle the inventor to a patent, his invention must, to a
certain extent, be beneficial to the community, and not be for an unlawful
object, or frivolous, or insignificant. 1 Mason, 182; 1 Pet. C. C. R. 322; 1
Bald. 303; 14 Pick. 217; Paine, 203.