eth-

A two-carbon chain of atoms.

English ether (Greek aithēr, upper air, because the ether was believed to occupy all space beyond the sphere of the moon).

This form is used to represent the ethyl radical, a chain of two carbon atoms (ether is the common name for diethyl ether, which contains two such chains separated by an oxygen atom); this appears in a few names of organic compounds, such as ethene, ethyne, ethambutol (a synthetic compound used to treat tuberculosis), and ethacrynic acid, a powerful diuretic drug. See also ethoxy‑.