Greek word · G109

ἀήρ

aēr

air

Air, especially the lower, thicker air near the earth. In early Greek it means mist or haze. In later cosmology it is distinguished from aithēr, the pure upper air or heavens. It is the zone between earth and the higher heavens.

Appears 7 times in 7 verses of the Greek New Testament. · Updated October 30, 2026

What it means

ἀήρ, ἀέρος, ὁ,

[in LXX: 2 Kings 22:12 (= Psa.17(18):11 שׁחק), Wi .8 ;]

in Hom., Hes., the lower air which surrounds the earth, as opposite to the purer αἰθήρ of the higher regions; generally, air (MM, VGT, see word): Acts 22:23, 1 Thessalonians 4:17, Revelation 9:2 16:17; of the air as the realm of demons, Ephesians 2:2; ἀ. δέρειν, of striving to no purpose, 1 Corinthians 9:26; εἰς ἀ. λαλεῖν, of speaking without effect, not being understood, 1 Corinthians 14:9.†

(AS)

From G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922), via STEPBible.org (CC BY 4.0).

In depth

From the study of Ephesians 2:2

Range of meaning: Air, especially the lower, thicker air near the earth. In early Greek it means mist or haze. In later cosmology it is distinguished from aithēr, the pure upper air or heavens. It is the zone between earth and the higher heavens.
Against the English: Every major English version says "air" except NLT ("unseen world"). The word is correct, but modern readers hear it with a modern picture of the atmosphere.
How it drifted: Modern science makes "air" a physical mixture of gases with no spiritual address. Some twentieth-century preaching applied it to broadcasting ("the airwaves"). Neither idea belongs to the first-century picture of a layered universe.
Used elsewhere in the period: Testament of Benjamin 3:4 has "the aerial spirit of Beliar". Philo (On the Giants 6–9) says the air is full of souls and spirit-beings. Diogenes Laertius 8.32 reports the Pythagorean saying that "the whole air is full of souls", called daimones. In 2 Enoch 29:4–5 the fallen angel is cast down to fly "in the air". The Ascension of Isaiah (7:9–12) puts Sammael and his hosts in the firmament. Compare also "the heavenly places" in Ephesians 6:12.

From the study of Revelation 16:17

Range of meaning: The air, especially the lower and denser atmosphere near the earth, as distinct from the upper heaven (aithēr) or the sky (BDAG s.v. ἀήρ). In some Jewish and Greco-Roman writings it is the region where spirits or demons live.
Against the English: 'Air' is accurate. Most readers will hear simply 'the atmosphere', which is right, though some ancient readers may also have heard the realm of spiritual powers.
Used elsewhere in the period: Ephesians 2:2 calls Satan 'the ruler of the authority of the air'. 1 Thessalonians 4:17 places the meeting with the Lord 'in the air'. Revelation 9:2 uses ἀήρ for the sky darkened by smoke from the abyss. Philo and later Jewish writings describe the air as filled with souls or spirits.

From the study of 1 Thessalonians 4:17

Range of meaning: Air. In Greek cosmology it is the lower, denser atmosphere around the earth, as opposed to aithēr, the bright upper region, and ouranos, heaven or the sky. In some Jewish and Hellenistic thought it is also the region where spirits live.
Against the English: Modern readers may run together 'in the air' and 'in heaven'. Paul does not say ouranos (heaven), the word he uses in v.16 for where the Lord descends from.
How it drifted: Popular retellings often skip from 'the air' to 'heaven' as if they were the same.
Used elsewhere in the period: Ephesians 2:2 speaks of 'the ruler of the power of the air.' Philo (On the Giants 6–9) describes the air as filled with souls. Revelation 9:2 and 16:17 use it of the lower sky.

Where it appears

Acts · 1

Acts 22:23 ἀέρα air

As they were shouting and throwing off their cloaks and tossing dust into the air,

Here: The everyday air around and just above them. They throw the dust upward and toward Paul, not onto their own heads as people did in mourning.

1 Corinthians · 2

1 Corinthians 9:26 ἀέρα [the] air

Therefore I do not run aimlessly; I do not fight like I am beating the air.

Here: The air around the fighter. Here it is the empty space a wild or shadow punch hits instead of a real target. It has no article, so simply 'air.'
1 Corinthians 14:9 ἀέρα [the] air

So it is with you. Unless you speak intelligible words with your tongue, how will anyone know what you are saying? You will just be speaking into the air.

Ephesians · 1

Ephesians 2:2 ἀέρος, air,

in which you used to walk when you conformed to the ways of this world and of the ruler of the power of the air, the spirit who is now at work in the sons of disobedience.

Here: The lower air between earth and the upper heavens. Jews and Greeks of the time widely held that spirits lived there. It places this ruler close to human life and above it, but below God's heaven.

1 Thessalonians · 1

1 Thessalonians 4:17 ἀέρα· [the] air;

After that, we who are alive and remain will be caught up together with them in the clouds to meet the Lord in the air. And so we will always be with the Lord.

Here: The lower sky between earth and heaven, where clouds are. Paul does not say heaven (ouranos). The meeting happens in the space between.

Revelation · 2

Revelation 9:2 ἀὴρ air

The star opened the pit of the Abyss, and smoke rose out of it like the smoke of a great furnace, and the sun and the air were darkened by the smoke from the pit.

Here: The lower air between earth and sky, the air people breathe and see through. Not only is the sun hidden; the whole atmosphere turns murky.
Revelation 16:17 ἀέρα, air,

Then the seventh angel poured out his bowl into the air, and a loud voice came from the throne in the temple, saying, “It is done!”

Here: The lower atmosphere, the space between earth and the upper heavens where people breathe and where storms form. It is the last part of the created world to be struck, and it produces the storm, earthquake and hail of verses 18–21. In Jewish and Greco-Roman thought the air could also be the realm of spirits (compare Ephesians 2:2).

Word data: STEPBible.org (CC BY 4.0), main text only.