1. A public proclamation; a manifesto or edict issued by authority. All placards or edicts are published in his name. (Howell)
2. Permission given by authority; a license; as, to give a placard to do something.
3. A written or printed paper, as an advertisement or a declaration, posted, or to be posted, in a public place; a poster.
4. An extra plate on the lower part of the breastplate or backplate.
5. [Cf. Placket] A kind of stomacher, often adorned with jewels, worn in the fifteenth century and later.
Origin: F, fr. Plaquer to lay or clap on, plaque plate, tablet; probably from Dutch, cf. D. Plakken to paste, post up, plak a flat piece of wood.