'Signboard' definitions:

Definition of 'signboard'

From: WordNet
noun
Structure displaying a board on which advertisements can be posted; "the highway was lined with signboards" [syn: signboard, sign]

Definition of 'Signboard'

From: GCIDE
  • Signboard \Sign"board`\, n. A board, placed on or before a shop, office, etc., on which ssome notice is given, as the name of a firm, of a business, or the like. [1913 Webster]