to have confidence in the truth, the existence, or the reliability of something, although without absolute proof that one is right in doing so: Only if one believes in something can one act purposefully.
verb (used with object)
2.
to have confidence or faith in the truth of (a positive assertion, story, etc.); give credence to.
3.
to have confidence in the assertions of (a person).
4.
to have a conviction that (a person or thing) is, has been, or will be engaged in a given action or involved in a given situation: The fugitive is believed to be headed for the Mexican border.
5.
to suppose or assume; understand (usually followed by a noun clause): I believe that he has left town.
Origin: 1150–1200;Middle Englishbileven, equivalent to bi-be- + leven,Old English (Anglian) gelēfan (cognate with Dutchgelooven,Germanglauben,Gothicgalaubjan)
O.E. belyfan "to believe," earlier geleafa (Mercian), gelefa (Northumbrian), gelyfan (W.Saxon) "believe," from P.Gmc. *ga-laubjan "hold dear, love" (cf. O.S. gilobian, Du. geloven, O.H.G. gilouben, Ger. glauben), from PIE base *leubh- "to like, desire" (see love). Spelling
beleeve is common till 17c.; then altered perhaps by influence of relieve. To believe on instead of in was more common in 16c. but now is a peculiarity of theology; believe of also sometimes was used in 17c.