From H7554; properly an expanse, that is, the firmament or (apparently) visible arch of the sky
KJV Usage: firmament.
Brown-Driver-Briggs' Hebrew Definitions
1. extended surface (solid), expanse, firmament a. expanse (flat as base, support) b. firmament (of vault of heaven supporting waters above) 1. considered by Hebrews as solid and supporting 'waters' above
Origin: from H7554
Parts of Speech: Noun Masculine