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).
Ether extract (EE) is the fat or lipid portion of the feed. The net energy system is generally thought to be more precise in estimating the energy value of feeds, particularly roughages. The net energy of feed is the portion that is available to the animal for maintenance or various productive purposes.