From Wikipedia, the free encyclopedia. Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula (CH 3 CO) 2 O. Commonly abbreviated Ac 2 O, it is the simplest isolable anhydride of a carboxylic acid and is widely used as a reagent in organic synthesis.o a decreasing extent, acetic anhydride is also prepared by the reaction of ketene (ethenone) with acetic acid at 45â55 Â°C and low pressure (0.05â0.2 bar).
Definition: The prefix (eu-) means good, well, pleasant or true. It is derived from the Greek eu meaning well and eus meaning good. Eubacteria (eu-bacteria) - kingdom in the bacteria domain. Bacteria are considered to be true bacteria, distinguishing them from archaebacteria.
Euâ¢rope. a continent in the W part of the landmass lying between the Atlantic and Pacific oceans, separated from Asia by the Ural Mountains on the E and the Caucasus Mountains and the Black and Caspian seas on the SE. In British usage, Europe sometimes contrasts with England.729,000,000; ab. 4,017,000 sq. mi.. Europe-the 2nd smallest continent (actually a vast peninsula of Eurasia); the British use `Europe' to refer to all of the continent except the British Isles. megalith, megalithic structure-memorial consisting of a very large stone forming part of a prehistoric structure (especially in western Europe).