(Source) In the figure, we show the structure of a general carbonyl compound with a double bond. When R4 is a Hydrogen atom, the compound is a carboxylic acid. A compound is said to be saturated when it has only C-C single bonds. The compound is saturated with the maximum number of hydrogen atoms it can bond with. Here we have a double bond, therefore, the compound is unsaturated. The first carbon bonded to the carbon atom is said to be the \\(\\alpha\\) position. The carbon bonded to this \\(\\alpha\\) carbon is called the \\(\\beta\\) carbon. Here R3 is the \\(\\alpha\\) bonded substituent, and R4 is the \\(\\beta\\) bonded substituent. Therefore, this compound is called an \\(\\alpha, \\beta\\)-unsaturated carboxylic acid.