from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Located or occurring on or near the surface of the earth.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Located or occurring at the Earth's surface, especially on land
from the GNU version of the Collaborative International Dictionary of English
- adj. Beneath the sky; in the open air; specifically (Geol.), taking place on the earth's surface, as opposed to subaqueous.
from The Century Dictionary and Cyclopedia
- In geology, formed, produced, or deposited in the open air, and not beneath the sea, or under water, or below the surface; not submarine or subterranean: thus, subaërial denudation or erosion: See æolian, 2.
Literally under the air (Wiktionary)