Dear Paul:

In ancient times the term "heavens" referred to the "sky" in three layers:

1) The First Layer is the "blue firmament." This is the region of the clouds (Gen. 1:20)

2) The Second Layer is the region of the stars.

3) The Third Layer is the region of God and His Angels.

This is why we see the term "heavens" as a plural.

The English word "heaven" derives from Germanic languages with a meaning of "sky" or "firmament", but in the 11th - 12th Century to the present was Christianized in its meaning to the "place where God dwells."

To answer your question precisely, the specific term "heaven" in English meaning the "dwelling place of God" is derived from heven around 1159, which derived from the Old English heofon dating to around 1000. Since the Old English word heofon dates to the beginning of the 11th Century and referred to the place where God dwells, it is likely the Christianized form of the word heaven derives some time earlier than A.D. 1000.

St. Paul talks about being taken into the Third Heaven (2 Cor 12:2). This Third Heaven is the third layer mentioned above -- the dwelling place of God and the Angels.

You may have also heard of the the 7th Heaven. There is a T.V. show by that name. This refers to the ancient Jewish mysticism contained in the Kabbalah, which recognizes seven heavens. The 7th Heaven is called Araboth, which is the dwelling place of God.

God Bless,
Bro. Ignatius Mary