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).
In a technical sense, Ethereum is a world computer. Harking back to the days of the mainframe, and probably about as fast, Ethereum can be viewed as a single computer that the whole world can use. It notionally has only a single processor (no multi-threading or parallel execution), but as much memory as required.