Cloud - Vine's Expository Dictionary of New Testament Words
Cloud[ 1,,G3509, nephos ]
denotes a cloudy, shapeless mass covering the heavens." Hence, metaphorically, of "a dense multitude, a throng," Hebrews 12:1.
[ 2,,G3507, nephele ]
"a definitely shaped cloud, or masses of clouds possessing definite form," is used, besides the physical element,
(a) of the "cloud" on the mount of transfiguration, Matthew 17:5;
(b) of the "cloud" which covered Israel in the Red Sea, 1 Corinthians 10:1-2;
(c), of "clouds" seen in the Apocalyptic visions, Revelation 1:7; Revelation 10:1; Revelation 11:12; Revelation 14:14-Revelation 14:16;
(d) metaphorically in 2 Peter 2:17, of the evil workers there mentioned; but RV, "and mists" (homichle), according to the most authentic mss. In 1 Thessalonians 4:17, the "clouds" referred to in connection with the rapture of the saints are probably the natural ones, as also in the case of those in connection with Christ's Second Advent to the earth. See Matthew 24:30; Matthew 26:64, and parallel passages. So at the Ascension, Acts 1:9.