(~s)
1.
A ~ is a flat piece of metal or stone with writing on it which is fixed to a wall or other structure to remind people of an important person or event.
After touring the hospital, Her Majesty unveiled a commemorative ~.
N-COUNT
2.
Plaque is a substance containing bacteria that forms on the surface of your teeth.
Deposits of ~ build up between the tooth and the gum.
N-UNCOUNT