Easton's Bible Dictionary
Is converse with God; the intercourse of the soul with God, not in contemplation or meditation, but in direct address to him. Prayer may be oral or mental, occasional or constant, ejaculatory or formal. It is a "beseeching the Lord" (Exodus 32:11); "pouring out the soul before the Lord" (1 Samuel 1:15); "praying and crying to heaven" (2 Chronicles 32:20); "seeking unto God and making supplication" (Job 8:5); "drawing near to God" (Psalm 73:28); "bowing the knees" (Ephesians 3:14).
Prayer presupposes a belief in the personality of God, his ability and willingness to hold intercourse with us, his personal control of all things and of all his creatures and all their actions.
Acceptable prayer must be sincere (Hebrews 10:22), offered with reverence and godly fear, with a humble sense of our own insignificance as creatures and of our own unworthiness as sinners, with earnest importunity, and with unhesitating submission to the divine will. Prayer must also be offered in the faith that God is, and is the hearer and answerer of prayer, and that he will fulfil his word, "Ask, and ye shall receive" (Matthew 7:7, 8; 21:22; Mark 11:24; John 14:13, 14), and in the name of Christ (16:23, 24; 15:16; Ephesians 2:18; 5:20; Colossians 3:17; 1 Peter 2:5).
Prayer is of different kinds, secret (Matthew 6:6); social, as family prayers, and in social worship; and public, in the service of the sanctuary.
Intercessory prayer is enjoined (Numbers 6:23; Job 42:8; Isaiah 62:6; Psalm 122:6; 1 Timothy 2:1; James 5:14), and there are many instances on record of answers having been given to such prayers, e.g., of Abraham (Genesis 17:18, 20; 18:23-32; 20:7, 17, 18), of Moses for Pharaoh (Exodus 8:12, 13, 30, 31; Exodus 9:33), for the Israelites (Exodus 17:11, 13; 32:11-14, 31-34; Numbers 21:7, 8; Deuteronomy 9:18, 19, 25), for Miriam (Numbers 12:13), for Aaron (Deuteronomy 9:20), of Samuel (1 Samuel 7:5-12), of Solomon (1 Kings 8; 2 Chronicles 6), Elijah (1 Kings 17:20-23), Elisha (2 Kings 4:33-36), Isaiah (2 Kings 19), Jeremiah (42:2-10), Peter (Acts 9:40), the church (12:5-12), Paul (28:8).
No rules are anywhere in Scripture laid down for the manner of prayer or the attitude to be assumed by the suppliant. There is mention made of kneeling in prayer (1 Kings 8:54; 2 Chronicles 6:13; Psalm 95:6; Isaiah 45:23; Luke 22:41; Acts 7:60; 9:40; Ephesians 3:14, etc.); of bowing and falling prostrate (Genesis 24:26, 52; Exodus 4:31; 12:27; Matthew 26:39; Mark 14:35, etc.); of spreading out the hands (1 Kings 8:22, 38, 54; Psalm 28:2; 63:4; 88:9; 1 Timothy 2:8, etc.); and of standing (1 Samuel 1:26; 1 Kings 8:14, 55; 2 Chronicles 20:9; Mark 11:25; Luke 18:11, 13).
If we except the "Lord's Prayer" (Matthew 6:9-13), which is, however, rather a model or pattern of prayer than a set prayer to be offered up, we have no special form of prayer for general use given us in Scripture.
Prayer is frequently enjoined in Scripture (Exodus 22:23, 27; 1 Kings 3:5; 2 Chronicles 7:14; Psalm 37:4; Isaiah 55:6; Joel 2:32; Ezek. 36:37, etc.), and we have very many testimonies that it has been answered (Psalm 3:4; 4:1; 6:8; 18:6; 28:6; 30:2; 34:4; 118:5; James 5:16-18, etc.).
"Abraham's servant prayed to God, and God directed him to the person who should be wife to his master's son and heir (Genesis 24:10-20).
"Samson prayed to God, and God showed him a well where he quenched his burning thirst, and so lived to judge Israel (Judges 15:18-20).
"Daniel prayed, and God enabled him both to tell Nebuchadnezzar his dream and to give the interpretation of it (Dan. 2: 16-23).
"The believers in Jerusalem prayed, and God opened the prison doors and set Peter at liberty, when Herod had resolved upon his death (Acts 12:1-12).
"Paul prayed that the thorn in the flesh might be removed, and his prayer brought a large increase of spiritual strength, while the thorn perhaps remained (2 Corinthians 12:7-10).
"Prayer is like the dove that Noah sent forth, which blessed him not only when it returned with an olive-leaf in its mouth, but when it never returned at all.", Robinson's Job.
Noah Webster's New International Dictionary of the English Language
1. (n.) One who prays; a supplicant.
2. (n.) The act of praying, or of asking a favor; earnest request or entreaty; hence, a petition or memorial addressed to a court or a legislative body.
3. (n.) The act of addressing supplication to a divinity, especially to the true God; the offering of adoration, confession, supplication, and thanksgiving to the Supreme Being; as, public prayer; secret prayer.
4. (n.) The form of words used in praying; a formula of supplication; an expressed petition; especially, a supplication addressed to God; as, a written or extemporaneous prayer; to repeat one's prayers.