From shachaq; a powder (as beaten small): by analogy, a thin vapor; by extension, the firmament -- cloud, small dust, heaven, sky.
see HEBREW shachaq
H7834. shachaq
שַׁ֫חַק noun masculineProv 9:20 dust, cloud (as fine, thin); — ׳שׁ absolute Psalm 89:7; 89:38, construct Isaiah 40:15; plural שְׁחָקִים Deuteronomy 33:25 +; —
1 fine dust, ׳שׁ מאֹזְנַיִם Isaiah 40:15 (simile of insignificance).
2 (thin) cloud, usually plural (often "" שָׁמַיִם), Deuteronomy 33:26 (poem), Isaiah 45:8; Jeremiah 51:9; Job 35:5; 36:28; 37:21; 38:37; Psalm 36:6; 57:11; 68:35; 77:18; 78:23; 108:5; opposed to תְּהוֺם Proverbs 3:20; 8:28; שׁ ׳עָבֵי 2 Samuel 22:12 = Psalm 18:12; = heavens, sky Job 37:18 (with חִרְקִיעַ), and (singular) Psalm 89:7; 89:38.
שִׁחֹר see שִׁיחוֺר.