plac ‧ ard /ˈplækɑːd $ -ərd/ BrE AmE noun [countable]
[ Date: 1400-1500 ; Language: French ; Origin: Old French plaquier 'to make flat' ]
a large notice or advertisement on a piece of card, which is put up or carried in a public place:
a huge placard saying ‘Welcome to Derbyville’