D defs.my
Entry 1 sense Webster, 1913

Useful

/yo͞os'-fəl/ · Use·ful · IPA /ˈjusfl̩/
01 a. Full of use, advantage, or profit; producing, or having power to produce, good; serviceable for any end or object; helpful toward advancing…
  1. 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; as, vessels and instruments useful in a family; books useful for improvement; useful knowledge; useful arts.
    “To what can I useful!” Milton.