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 is the first of the five elements of the universe as described by Ayurveda, a sister science of yoga. Ayurvedic teachings state that the universe is composed of five elements: ether, air, fire, water and earth. Ether is considered to be the most subtle of the five elements. Ether is sometimes referred to as space because it is the space that the other elements fill. Ether has the properties of lightness, airiness and spirituality. It has also been equated by some with the concept of consciousness. Yoga practice can help increase one's awareness of ether.