Esters are formed between alcohols and organic acids. A water molecule is produced as a by-product.

In the example shown on the left ethanol reacts with methanol to form ethylmethanoate. The name is made up of two parts. The "ethyl" part of the word comes from "ethanol" where the letters "anol" are replaced with "yl". The "methanoate" part of the word comes from "methanoic acid" the letters "ic" are replaced with "ate"