Webster's Revised Unabridged Dictionary (1828)

Believe, verb transitive.

1. To credit upon the authority or testimony of another; to be persuaded of the truth of something upon the declaration of another, or upon evidence furnished by reasons, arguments, and deductions of the mind, or by other circumstances, than personal knowledge.
   • When we believe upon the authority of another, we always put confidence in his veracity.
   • When we believe upon the authority of reasoning, arguments, or a concurrence of facts and circumstances, we rest our conclusions upon their strength or probability, their agreement with our own experience, &c.
2. To expect or hope with confidence; to trust.
   • I had fainted, unless I had believed to see the goodness of the Lord in the land of the living. (Ps. 27)

Believe, verb intransitive.

1. To have a firm persuasion of any thing. In some cases, to have full persuasion, approaching to certainty; in others, more doubt is implied. It is often followed by in or on, especially in the scriptures.
   • To believe in, is to hold as the object of faith.
     • Ye believe in God, believe also in me. (John 14)
   • To believe on, is to trust, to place full confidence in, to rest upon with faith.
     • To them gave he power to become the sons of God, even to them that believe on his name. (John 1)
   • But there is no ground for much distinction.
2. In theology, to believe sometimes expresses a mere assent of the understanding to the truths of the gospel.
   • As in the case of Simon. (Acts 8)
   • In others, the word implies, with this assent of the mind, a yielding of the will and affections, accompanied with a humble reliance on Christ for salvation. (John 1:12; 3:15)
3. In popular use and familiar discourse, to believe often expresses an opinion in a vague manner, without a very exact estimate of evidence, noting a mere preponderance of opinion, and is nearly equivalent to think or suppose.

Webster's Revised Unabridged Dictionary (1913)

Imp. and p.p. Believed; p.pr. and vb.n. Believing.

Origin:  OE. bileven (with pref. be- for AS. ge-), fr. AS. gelfan, gelfan; akin to D. gelooven, OHG. gilouban, G. glauben, OS. gilbian, Goth. galaubjan, and Goth. liubs dear.

Be-lieve, verb transitive.

1. To exercise belief in; to credit upon the authority or testimony of another; to be persuaded of the truth of, upon evidence furnished by reasons, arguments, and deductions of the mind, or by circumstances other than personal knowledge; to regard or accept as true; to place confidence in; to think; to consider; as, to believe a person, a statement, or a doctrine.
   • Our conqueror (whom I now Of force believe almighty). (Milton)
   • King Agrippa, believest thou the prophets? (Acts 26:7)
   • Often followed by a dependent clause. I believe that Jesus Christ is the Son of God. (Acts 8:37)

Be-lieve, verb intransitive.

1. To have a firm persuasion, esp. of the truths of religion; to have a persuasion approaching to certainty; to exercise belief or faith.
   • Lord, I believe; help thou mine unbelief. (Mark 9:24)
   • With the heart man believeth unto righteousness. (Rom. 10:10)
2. To think; to suppose.
   • I will not believe so meanly of you. (Fielding)

To believe in.

1. To believe that the subject of the thought (if a person or thing) exists, or (if an event) that it has occurred, or will occur; -- as, to believe in the resurrection of the dead.
   • She does not believe in Jupiter. (J.H. Newman)
2. To believe that the character, abilities, and purposes of a person are worthy of entire confidence; -- especially that his promises are wholly trustworthy.
   • Let not your heart be troubled: ye believe in God, believe also in me. (John 14:1)
3. To believe that the qualities or effects of an action or state are beneficial: as, to believe in sea bathing, or in abstinence from alcoholic beverages.
4. To believe on, to accept implicitly as an object of religious trust or obedience; to have faith in.

Webster's Universal Dictionary (1937)

Origin: Middle English faith, feith; Old French feid; Latin fides, faith, belief, trust, from fidere, to trust, confide in.

Definitions:

1. The assent of the mind to the truth of what is declared by another, resting on his authority and veracity, without other evidence, or on probable evidence of any kind; assent of the mind to a statement or proposition of another, on the ground of the manifest truth of such statement or proposition; firm and earnest belief, on probable evidence of any kind; as, I have strong faith, or no faith, in the testimony of a witness.
2. The assent of the mind to what is given forth as a revelation of man's relation to God and the infinite; a settled conviction in regard to religion; specifically, in Christian theology,
   1. Belief in the historic truthfulness of the Scripture narrative and the supernatural origin of its teaching; also called historical or speculative faith.
   2. The assent of the mind to the truth of divine revelation, on the authority of God's testimony, accompanied by a cordial assent of the will or approbation of the heart; an entire confidence or trust in God's character and declarations, and in the character and doctrines of Christ, with an unreserved surrender of the will to his guidance, and dependence on his merits for salvation; also called evangelical, justifying, or saving faith.
3. The object of belief; a doctrine or system of doctrines believed, whether scientific, political, or religious; especially, a creed; a religious system; specifically, the Christian religion.
4. Faithfulness; fidelity; a strict adherence to duty and fulfilment of promises.
5. Word or honor pledged; promise given; fidelity; as, violated his plighted faith.
6. Credibility or truth [Rare.]

Syn: Belief, trust, confidence, credence, fidelity, conviction, creed, tenets, doctrine, opinion.

Wolfram Alpha

Definitions:

1. Accept as true; take to be true.
2. Judge or regard; look upon; judge.
3. Be confident about something.
4. Follow a credo; have a faith; be a believer.
5. Credit with veracity.

Pronunciation: buhl'eev.

Hyphenation: be-lieve (7 letters, 2 syllables).

First Known Use in English: 1549 (European Renaissance).

Word Origins: Old English.

Inflected Forms: Believed, believing, believes.

Synonyms: Conceive, consider, think, trust.

Antonym: Disbelieve.

Narrower Terms: Bank, believe, believe in, buy, infer, rely, swallow, swear, trust, understand, consider, esteem, feel, hold, look on.

Broader Terms: Accept, evaluate, judge, pass judgment, anticipate, expect, believe, credit

Rhymes: Achieve, aggrieve, bereave, cleave, conceive, deceive, disbelieve, greave, grieve, heave, interleave, interweave, leave, misconceive, misperceive. achieve | aggrieve | bereave | cleave | conceive | deceive | disbelieve | greave | grieve | heave | interleave | interweave | leave | misconceive | misperceive | ... (total: 29) (based on typical American pronunciation)

Oxford English Dictionary

1. Accept that (something) is true, especially without proof:
   Examples:
   • The superintendent believed Lancaster's story.
   • Some 23 per cent believe that smoking keeps down weight.
   • His long-suffering wife, Nora, faces an everyday struggle to find money for food and other essentials.
   1. Accept the statement of (someone) as true:
      • He didn't believe her.
      • Many local people believed him when he spoke of the right or wrong siting of houses or tombs.
   2. Have religious faith:
      • There are those on the fringes of the Church who do not really believe.
      • Was it lifted up whole and intact to heaven, as the Catholic faith believes?
   3. (Believe something of) Feel sure that (someone) is capable of doing something:
      • I wouldn't have believed it of Lavinia--what an extraordinary woman!
      • I couldn't believe it of him because he had behaved so normally at home.
2. Hold (something) as an opinion; think:
   • I believe we've already met.
   • (Believe someone/thing to be) Four men were believed to be trapped.

Synonyms:

1. I don't believe you.
   • Be convinced by, trust, have confidence in, consider honest, consider truthful.
2. If you believe that story you will believe anything.
   • Regard as true, accept as true, accept, be convinced by, give credence to, credit, give credit to, trust, put confidence in, count on, rely on, depend on.
   • (Informal) Swallow, {swallow something hook, line, and sinker}, fall for, go for, buy, take as gospel.
3. Police believe they've identified the smuggler. I believe he worked for you.
   • Think, be of the opinion that, think it likely that, have an idea that, imagine, feel, have a feeling, hold, maintain, suspect, suppose, assume, presume, conjecture, surmise, postulate that, theorize that, conclude, come to the conclusion that, deduce; understand, be given to understand, take it, gather, fancy, guess, dare say.
   • (North American) Figure.

Faith is something superior to knowledge and is its criterion. Conjecture, which is only a feeble supposition, is a counterfeit faith.

Now he is faithful who keeps inviolably what is entrusted to him.

We have discovered faith to be the first movement towards salvation. After faith, fear, hope, and repentance (accompanied by temperance and patience) lead us to love and knowledge.

We say, then, that faith must not be inert and alone. Rather, it should be accompanied with investigation. For I do not say that we are not to inquire at all.

Trusting is more than faith. For when one has believed that the Son of God is our Teacher, he trusts that His teaching is true.

Faith, so to speak, is a comprehensive knowledge of the essentials. And knowledge is the strong and sure demonstration of what is received by faith. It is built upon faith by the Lord's teaching.

In my opinion, the faith they possessed was firm, for it was followed by works of faith.

Origen (184/185-253/254)--Who enters on a voyage, contracts a marriage, becomes the father of children, or sows seed into the ground--without believing that better things will result from doing so? ... If the hope and belief of a better future is the support of life in every uncertain enterprise, ... why should not this faith rather be rationally accepted by him who believes on better grounds ... in the existence of a God who was the Creator of all these things?

Cyprian (c. 200-258)--[WRITTEN TO CHRISTIANS FACING MARTYRDOM:] It is written that the just live by faith. If you are just and live by faith--if you truly believe in Christ--why do you not embrace the assurance that you are called to Christ? Why do you not rejoice that you are freed from the devil? For you are about to be with Christ and are secure of the Lord's promise.

St. John Chrysostom (347-407)--"Believeth all things." "For it doth not merely hope," saith he, "but also believeth from its great affection."

Augustine (354-430)--Since faith, then, is in our power, inasmuch as every one believes when he likes, and, when he believes, believes voluntarily; our next inquiry, which we must conduct with care, is, What faith it is which the apostle commends with so much earnestness? For indiscriminate faith is not good. Accordingly we find this caution: �Brethren, believe not every spirit, but try the spirits whether they are of God.� Nor must the clause in commendation of love, that it �believeth all things,� be so understood as if we should detract from the love of any one, if he refuses to believe at once what he hears. For the same love admonishes us that we ought not readily to believe anything evil about a brother; and when anything of the kind is said of him, does it not judge it to be more suitable to its character not to believe? Lastly, the same love, �which believeth all things,� does not believe every spirit. Accordingly, charity believes all things no doubt, but it believes in God. Observe, it is not said, Believes in all things. It cannot therefore be doubted that the faith which is commended by the apostle is the faith whereby we believe in God.