From BiblePortal Wikipedia

Vine's Expository Dictionary of OT Words [1]

A. Verb.

'Âman ( אָמַן , Strong'S #539), “to be firm, endure, be faithful, be true, stand fast, trust, have belief, believe.” Outside of Hebrew, this word appears in Aramaic (infrequently), Arabic, and Syriac. It appears in all periods of biblical Hebrew (about 96 times) and only in the causative and passive stems.In the passive stem, 'âman has several emphases. First, it indicates that a subject is “lasting” or “enduring,” which is its meaning in Deut. 28:59: “Then the Lord will make thy plagues wonderful, and the plagues of thy seed, even great plagues, and of long continuance, and sore sicknesses, and of long continuance.” It also signifies the element of being “firm” or “trustworthy.” In Isa. 22:23, 'âman refers to a “firm” place, a place into which a peg will be driven so that it will be immovable. The peg will remain firmly anchored, even though it is pushed so hard that it breaks off at the point of entry (Isa. 22:25). The Bible also speaks of “faithful” people who fulfill their obligations (cf. 1 Sam. 22:14; Prov. 25:13).

The nuance meaning “trustworthy” also occurs: “He that is of a faithful spirit concealeth the matter” (Prov. 11:13; cf. Isa. 8:2). An officebearer may be conceived as an “entrusted one”: “He removeth away the speech of the trusty [entrusted ones], and taketh away the understanding of the aged” (Job 12:20). In this passage, 'âman is synonymously parallel (therefore equivalent in meaning) to “elders” or “officebearers.” Thus, it should be rendered “entrusted ones” or “those who have been given a certain responsibility (trust).” Before receiving the trust, they are men “worthy of trust” or “trustworthy” (cf. 1 Sam. 2:35; Neh. 13:13).

In Gen. 42:20 (the first biblical appearance of this word in this stem), Joseph requests that his brothers bring Benjamin to him; “so shall your words be verified,” or “be shown to be true” (cf. 1 Kings 8:26; Hos. 5:9). In Hos. 11:12, 'âman contrasts Judah’s actions (“faithful”) with those of Ephraim and Israel (“deceit”). So here 'âman represents both “truthfulness” and “faithfulness” (cf. Ps. 78:37; Jer. 15:18). The word may be rendered “true” in several passages (1 Kings 8:26; 2 Chron. 1:9; 6:17).

A different nuance of 'âman is seen in Deut. 7:9: “… the faithful God, which keepeth covenant and mercy.…” There is a good reason here to understand the word 'âman as referring to what God has done (“faithfulness”), rather than what He will do (“trustworthy”), because He has already proved Himself faithful by keeping the covenant. Therefore, the translation would become, “… faithful God who has kept His covenant and faithfulness, those who love Him kept …” (cf. Isa. 47:7).

In the causative stem, 'âman means “to stand fast,” or “be fixed in one spot,” which is demonstrated by Job 39:24: “He [a war horse] swalloweth the ground with fierceness and rage: neither believeth he that it is the sound of the trumpet.”

Even more often, this stem connotes a psychological or mental certainty, as in Job 29:24: “If I laughed on them, they believed it not.” Considering something to be trustworthy is an act of full trusting or believing. This is the emphasis in the first biblical occurrence of 'âman  : “And [Abram] believed in the Lord; and he counted it to him for righteousness” (Gen. 15:6). The meaning here is that Abram was full of trust and confidence in God, and that he did not fear Him (v. 1). at was not primarily in God’s words that he believed, but in God Himself. Nor does the text tell us that Abram believed God so as to accept what He said as “true” and “trustworthy” (cf. Gen. 45:26), but simply that he believed in God. In other words, Abram came to experience a personal relationship to God rather than an impersonal relationship with His promises. Thus, in Exod. 4:9 the meaning is, “if they do not believe in view of the two signs,” rather than, “if they do not believe these two signs.” The focus is on the act of believing, not on the trustworthiness of the signs. When God is the subject or object of the verb, the Septuagint almost always renders this stem of 'âman with pisteuo (“to believe”) and its composites. The only exception to this is Prov. 26:25.

A more precise sense of 'âman does appear sometimes: “That they may believe that the Lord … hath appeared unto thee” (Exod. 4:5; cf. 1 Kings 10:7).

In other instances, 'âman has a cultic use, by which the worshiping community affirms its identity with what the worship leader says (1 Chron. 16:32). The “God of the 'âman w (2 Chron. 20:20; Isa. 65:16) is the God who always accomplishes what He says; He is a “God who is faithful.”

B. Nouns.

'Ěmûnâh ( אֱמֻנָה ,Strong'S #530), “firmness; faithfulness; truth; honesty; official obligation.” In Exod. 17:12 (the first biblical occurrence), the word means “to remain in one place”: “And his [Moses’] hands were steady until the going down of the sun.” Closely related to this use is that in Isa. 33:6: “And wisdom and knowledge shall be the stability of thy times.…” In passages such as 1 Chron. 9:22, 'ĕmûnâh appears to function as a technical term meaning “a fixed position” or “enduring office”: “All these which were chosen to be porters in the gates were two hundred and twelve. These were reckoned by their genealogy in their villages, whom David and Samuel the seer did ordain in their set [i.e., established] office.”The most frequent sense of 'ĕmûnâh is “faithfulness,” as illustrated by 1 Sam. 26:23: “The Lord render to every man his righteousness and his faithfulness.…” The Lord repays the one who demonstrates that he does what God demands.

Quite often, this word means “truthfulness,” as when it is contrasted to false swearing, lying, and so on: “Run ye to and fro through the streets of Jerusalem, and see now, and know, and seek in the broad places thereof, if ye can find a man, if there be any that executeth judgment, that seeketh the truth [i.e., honesty]” (Jer. 5:1; cf. Jer. 5:2). Here 'ĕmûnâh signifies the condition of being faithful to God’s covenant, practicing truth, or doing righteousness. On the other hand, the word can represent the abstract idea of “truth”: “This is a nation that obeyeth not the voice of the Lord their God, nor receiveth correction: truth [ 'ĕmûnâh ] is perished, and is cut off from their mouth” (Jer. 7:28).

These quotations demonstrate the two senses in which 'ĕmûnâh means “true”—the personal sense, which identifies a subject as honest, trustworthy, faithful, truthful (Prov. 12:22); and the factual sense, which identifies a subject as being factually true (cf. Prov. 12:27), as opposed to that which is false.

The essential meaning of 'ĕmûnâh is “established” or “lasting,” “continuing,” “certain.” So God says, “And in mercy shall the throne be established: and he shall sit upon it in truth in the tabernacle of David, judging, and seeking judgment, and hasting righteousness” (cf. 2 Sam. 7:16; Isa. 16:5). Thus, the phrase frequently rendered “with lovingkindness and truth” should be rendered “with perpetual (faithful) lovingkindness” (cf. Josh. 2:14). He who sows righteousness earns a “true” or “lasting” reward (Prov. 11:18), a reward on which he can rely.

In other contexts, 'ĕmûnâh embraces other aspects of the concept of truth: "[The Lord] hath remembered his mercy and his truth toward the house of Israel …” (Ps. 98:3). Here the word does not describe the endurance of God but His “truthfulness”; that which He once said He has maintained. The emphasis here is on truth as a subjective quality, defined personally. In a similar sense, one can both practice (Gen. 47:29) and speak the “truth” (2 Sam. 7:28). In such cases, it is not a person’s dependability (i.e., others can act on the basis of it) but his reliability (conformity to what is true) that is considered. The first emphasis is subjective and the second objective. It is not always possible to discern which emphasis is intended by a given passage.

'Emeth ( אֱמֶת , Strong'S #571), “truth; right; faithful.” This word appears 127 times in the Bible. The Septuagint translates it in 100 occurrences as “truth” ( aletheia ) or some form using this basic root. In Zech. 8:3, Jerusalem is called “a city of truth.” Elsewhere, 'emeth is rendered as the word “right” ( dikaios ) “Howbeit thou art just in all that is brought upon us; for thou hast done right, but we have done wickedly …” (Neh. 9:33). Only infrequently (16 times) is 'emeth translated “faithful” ( pistis ), as when Nehemiah is described as “a faithful man, and feared God above many” (Neh. 7:2).

C. Adverb.

'Âmên ( אָמֵן , Strong'S #543), “truly; genuinely; amen; so be it.” The term 'âmên is used 30 times as an adverb. The Septuagint renders it as “truly” ( lethinos ) once; transliterates it as “amen” three times; and translates it as “so be it” ( genoito ) the rest of the time. This Hebrew word usually appears as a response to a curse that has been pronounced upon someone, as the one accursed accepts the curse upon himself. By so doing, he binds himself to fulfill certain conditions or else be subject to the terms of the curse (cf. Deut. 29:15-26).Although signifying a voluntary acceptance of the conditions of a covenant, the 'âmên was sometimes pronounced with coercion. Even in these circumstances, the one who did not pronounce it received the punishment embodied in the curse. So the 'âmên was an affirmation of a covenant, which is the significance of the word in Num. 5:22, its first biblical occurrence. Later generations or individuals might reaffirm the covenant by voicing their 'âmên (Neh. 5:1-13; Jer. 18:6).

In 1 Kings 1:36, 'âmên is noncovenantal. It functions as an assertion of a person’s agreement with the intent of a speech just delivered: “And Benaiah the son of Jehoiada answered the king, and said, Amen: the Lord God of my lord the king say so too.” However, the context shows that Benaiah meant to give more than just verbal assent; his 'âmên committed him to carry out the wishes of King David. It was a statement whereby he obligated himself to do what David had indirectly requested of him (cf. Neh. 8:6).

King James Dictionary [2]

BELIE'VE, 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.  Psalms 27

BELIE'VE, 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 . Johnson. But there is no ground for much distinction.

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.

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 Dictionary [3]

(1): (n.) 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.

(2): (v. i.) To think; to suppose.

(3): (v. i.) To have a firm persuasion, esp. of the truths of religion; to have a persuasion approaching to certainty; to exercise belief or faith.

Hawker's Poor Man's Concordance And Dictionary [4]

See Belief