Is flavour a common noun

Yes, the noun 'flavor' is a common noun; a general Word for the quality of something detected by the sense of taste; a general Word for a substance added to food or drink that conveys a desired taste; a general Word for a characteristic or most noticeable quality of something; a Word for any flavor of any kind.

The Word 'flavor' is also a verb: flavor, flavors, flavoring, flavored.