Whelk, a marine (saltwater) snail. The common whelk, which grows up to about four inches (10 cm) in length, is found in the Atlantic on the coasts of Europe and North America. In parts of Europe it is a popular food. The common whelk has a thick, spiraled, ridged shell with a large opening. The shell is gray to yellowish-brown. With its filelike tongue the common whelk bores into the shells of oysters, mussels, and other shellfish and eats the soft parts. The whelk is preyed upon by cod and certain other fish.

Some kinds of whelks yield red and purple dyes. The Phoenicians made Tyrian purple from some of these.

The common wheik is Buccinum undatum of the family Buccinidae. Tyrian purple was obtained from whelks of the genus Murex, of the family Muricidae.