Definition of greeting card is …

A. a piece of thick, stiff paper or thin pasteboard, in particular one used for writing or printing on

B. an illustrated piece of card or high quality paper featuring an expression of friendship or other sentiment

C. material manufactured in thin sheets from the pulp of wood or other fibrous substances, used for writing, drawing, or printing on

D. a written or printed work consisting of pages glued or sewn together along one side and bound in covers