Fatty acids are carboxylic acids that have an aliphatic tail consisting of a varying number of carbon atoms.
Carbon atoms that form a fatty acid can be linked by either single or double bonds. This allows us to categorize fatty acids as saturated and unsaturated. Saturated fatty acids do not have any double bonds between the carbon atoms. Unsaturated fatty acids have at least one set of carbon atoms that are linked by a double bond. It is possible to convert unsaturated fatty acids to saturated fatty acids by a process known as hydrogenation, which converts double bonds to single by linking hydrogen atoms to the carbon atoms that formed a double bond.
The fatty acid mentioned in the question has two chains with single bonds and one with double bonds. The presence of a double bond allows the fatty acid to be categorized as an unsaturated fatty acid.