An amide is a type of organic compound that contains a carbonyl group (C=O) directly attached to a nitrogen atom (N). They are derived from carboxylic acids, where the hydroxyl group (–OH) is replaced by an amine group (–NH2, –NHR, or –NR2). Amides are commonly found in proteins and are important in various biological processes. Amides can be classified into primary, secondary, and tertiary amides based on the number of carbon-containing groups attached to the nitrogen. They are known for their stability and can be found in many pharmaceuticals and industrial chemicals. Their properties make them useful in the synthesis of various compounds, including peptides and nylon.