What is the meaning of the word root "aceto"?

I believed that "aceto" meant a methyl attached to a carbonyl group. For example, as in acetamide. Then, why do we name $\ce{CH3C\bond{3}N}$ as acetonitrile, even though it does not have any carbonyl group?


2 Answers 2


The root "acet-", according to wiki, is derived from latin acētum, meaning vinegar, i.e. diluted acetic acid. Consequently, direct derivatives of acetic acid, like acetamide and acetonitrile are called so. Also, acetone called so because it can be produced from acetic acid (directly or by dry distillation of calcium acetate)

What isn't obvious is why acetonitrile is considered a derivative of acetic acid and why nitriles in general are considered derivatives of carboxilic acids. Partially it's tradition and partially it's because compounds with carbon skeleton and oxidation state of carbon atoms unchanged are often rather easy to convert into each other.

  • $\begingroup$ I suppose that back in those days, one could have obtained acetonitrile by dehydration of acetamide, although I don't know if that was indeed the motivation for the name. $\endgroup$ Mar 25, 2018 at 17:28
  • 3
    $\begingroup$ A common misconception is that a nitrile is the group CN (triple bond) when in fact the nitrile is the triple bonded nitrogen. CH3CN is acetonitrile and "cyclohexyl nitrile" is cyclohexylCARBOnitrile. $\endgroup$
    – user55119
    Mar 25, 2018 at 18:15

Acetamide (ethanamide) is an organic compound with the formula CH3-CO-NH2. It is the simplest amide derived from acetic acid.

Acetonitrile is the chemical compound with the formula CH 3-CN. This colorless liquid is the simplest organic nitrile

In organic chemistry, acetyl is a moiety, with chemical formula CH3-CO. It is sometimes represented by the symbol Ac.


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