Answer:

cockle

Answer	Crossword Clue
COCKLE	Bivalve
COCKLE	Marine mollusk
COCKLE	Heart part?

COCKLE	Edible shellfish.
COCKLE	Shellfish.
COCKLE	Seashell
COCKLE	Certain shell
COCKLE	Wrinkle

Crossword

a puzzle consisting of a grid of squares and blanks into which words crossing vertically and horizontally are written according to clues.