aðr

Aër is a historical or stylistic spelling used in some European languages to denote air, particularly in older or literary texts. It is sometimes written with a diaeresis (aër) to indicate that the vowels should be pronounced separately, reflecting its etymological origins rather than contemporary orthography.

Etymology and usage: The form aër derives from Latin aër, itself from the Greek aēr (air). In classical and early modern writings, aër appeared in discussions of the atmosphere, weather, and the concept of air as a primordial element. In some philosophical and alchemical traditions, aër was treated as the element associated with air, alongside earth, fire, and water, and sometimes linked to the broader idea of aether or ether.

Modern usage: In contemporary languages, aër survives mainly as a historical or scholarly variant found in dictionaries, philological works, or poetic texts. It is not part of standard modern orthography outside of specific linguistic or historical contexts. The more common modern forms for the same concept are air in English, luft in German, aire in French, and so on. The root also underpins the modern prefix aero- and terms such as aerial, aerodynamics, and aerospace, which descend from the same Greek origin meaning air.

See also: aether, ether; aero-, aer–; air.