/ plæk; NAmE ; BrE also plɑːk/ noun
1.
[ C ] a flat piece of stone, metal, etc., usually with a name and dates on, attached to a wall in memory of a person or an event
2.
[ U ] a soft substance that forms on teeth and encourages the growth of harmful bacteria
—compare scale
••
WORD ORIGIN
mid 19th cent.: from French , from Dutch plak tablet, from plakken to stick.