Easton's Bible Dictionary (1897)/Air

Air the atmosphere, as opposed to the higher regions of the sky (1 Thessalonians 4:17; Revelation 9:2; 16:17). This word occurs once as the rendering of the Hebrew Ruah (Job 41:16); elsewhere it is the rendering of Shamaiyim, usually translated "heavens."

The expression "to speak into the air" (1 Corinthians 14:9) is a proverb denoting to speak in vain, as to "beat the air" (1 Corinthians 9:26) denotes to labour in vain.