In natural science, subaerial (literally "under the air") has been used since 1833,[1] notably in geology and botany, to describe features and events occurring or formed on or near the Earth's land surface.[1] They are thus exposed to Earth's atmosphere. This may be contrasted with subaqueous[2] events or features located below a water surface, submarine events or features located below a sea surface, subterranean events or features located below ground, or subglacial events or features located below glacial ice such as ice sheets.