1 If the invitation says black tie, women should wear a floor-length, evening gown. 2  A tuxedo is mandatory if you're a man. 3  This is your chance to dress as if you were headed to the Oscars. 4  Black tie optional means that wearing a tuxedo or long evening gown is not mandatory, but guests should feel free to do so.
Ether is an organic functional group consisting of a disubstituted oxygen, or an oxygen atom bonded to 2 carbon atoms (if adjacent to a ketone, functional group is then called an ester).
diethyl ether diÂ·ethÂ·yl ether (dÄ«-Äth'Él) n. A pungent, volatile, highly flammable liquid derived from the distillation of ethyl alcohol with sulfuric acid and widely used as an inhalation anesthetic. Also called ethyl ether, ethyl oxide, sulfuric ether.