/plɑ:k; [US] plæk; plæk/
n flat (usu round) piece of stone, metal or porcelain fixed on a wall as an ornament or a memorial （装于墙上作饰物或纪念物的石质、金属或瓷制的）饰板（通常为圆形）
*A simple plaque marks the spot where the martyr died. 有一块朴素的饰板用以纪念该烈士的殉难处.

/plɑ:k; [US] plæk; plæk/ n [U] (medical 医) soft substance that forms on teeth and encourages the growth of harmful bacteria 牙斑
*It is necessary to remove plaque by brushing one's teeth. 需刷牙以去除牙斑. Cf 参看 tartar1 1.

n
[Date: 1800-1900; Language: French;Origin:Dutch plak, from plakken 'to stick']
[C]
a piece of flat metal, wood, or stone with writing on it, used as a prize in a competition or attached to a building to remind people of an event or person
　The team's coach was given a plaque.
commemorative plaque
(=a plaque to help people remember something important)
[U]
a harmful substance which forms on your teeth, which bacteria can live and breed in