They are characterized by having a -COOH (carboxyl) grouping. They are named with the prefix indicating the number of carbons followed by the ending -oic or -ic (recommendation C-401.1).
When the -COOH group acts as a substituent, the name is constructed by starting the structure to which it is attached (ending in carboxylic), followed by the word acid.
However, there are many common names that are commonly used:
The R-CO- grouping is called acyl. The name is constructed from the corresponding starting acid by substituting the ending -oic (-ic) for -yl, (recommendation C-403.1) and is useful for naming some acid derivatives and when acting as substituents.
Nomenclature of the salts of carboxylic acids
Salts of acids consist of a cation and the anion derived from the corresponding carboxylic acid. They are designated by the name of the acid ending in -ate followed by the name of the cation (recommendation C-461.1).