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.
euphemism (n.). 1650s, from Greek euphemismos use of a favorable word in place of an inauspicious one, from euphemizein speak with fair words, use words of good omen, from eu- good, well (see) + pheme speech, voice, utterance, a speaking, from phanai speak (see (n.)).