mid-13c. in the sense "sequence of sensations passing through a sleeping person's mind" (also as a verb), probably related to Old Norse draumr, Danish drøm, Swedish dröm, Old Saxon drom "merriment, noise," Old Frisian dram "dream," Dutch droom, Old High German troum, German traum "dream," perhaps from West Germanic *draugmas "deception, illusion, phantasm" (cf. Old Saxon bidriogan, Old High German triogan, German trügen "to deceive, delude," Old Norse draugr "ghost, apparition"). Possible cognates outside Germanic are Sanskrit druh- "seek to harm, injure," Avestan druz- "lie, deceive."
But Old English dream meant only "joy, mirth, noisy merriment," also "music." And much study has failed to prove that Old English dream is the root of the modern word for "sleeping vision," despite being identical in spelling. Either the meaning of the word changed dramatically or "vision" was an unrecorded secondary Old English meaning of dream, or there are two separate words here. OED offers this theory: "It seems as if the presence of dream 'joy, mirth, music,' had caused dream 'dream' to be avoided, at least in literature, and swefn, lit. 'sleep,' to be substituted" ....
Words for "sleeping vision" in Old English were mæting and swefn. Old English swefn originally meant "sleep," as did a great many Indo-European "dream" nouns, e.g. Lithuanian sapnas, Old Church Slavonic sunu, and the Romanic words (French songe, Spanish sueño, Italian sogno all from Latin somnium (from PIE *swep-no-; cognate with Greek hypnos; see somnolence; Old English swefn is from the same root). Dream in the sense of "ideal or aspiration" is from 1931, from earlier sense of "something of dream-like beauty or charm" (1888).
c.1200 in the current sense, from dream (n.). Old English verb dremen meant "rejoice; play music." Related: Dreamed; dreaming.
dream (drēm)
n.
A series of images, ideas, emotions, and sensations occurring involuntarily in the mind during certain stages of sleep.
To invent; confect in the mind: Julian has to start dreaming up a story/ conceptions of living dreamed up by such groups as the Mormons (1940s+)
God has frequently made use of dreams in communicating his will to men. The most remarkable instances of this are recorded in the history of Jacob (Gen. 28:12; 31:10), Laban (31:24), Joseph (37:9-11), Gideon (Judg. 7), and Solomon (1 Kings 3:5). Other significant dreams are also recorded, such as those of Abimelech (Gen. 20:3-7), Pharaoh's chief butler and baker (40:5), Pharaoh (41:1-8), the Midianites (Judg. 7:13), Nebuchadnezzar (Dan. 2:1; 4:10, 18), the wise men from the east (Matt. 2:12), and Pilate's wife (27:19). To Joseph "the Lord appeared in a dream," and gave him instructions regarding the infant Jesus (Matt. 1:20; 2:12, 13, 19). In a vision of the night a "man of Macedonia" stood before Paul and said, "Come over into Macedonia and help us" (Acts 16:9; see also 18:9; 27:23).