As a technical term, the item of goods-for-sale being displayed. There is also a certain place in the commercial port at Athens, to which the display-items used to be brought, called this.[1] It is the Attic custom, to designate actual places by the things in the place.[2]
[The] Deigma was a place in Peiraieus, where many foreigners and citizens used to gather and converse. Aristophanes adds "of the lawsuits" [to the noun dei=gma], so that he can display and criticize the Athenians as litigious: "in the Deigma of the Lawsuits what terrible troublemakers did I hear in dispute".[3]
[The word] deigma also means proof. Aristophanes [writes]: "as proof of his [sc. style of] life, he was throwing out feathers in front of the doors".[4] As a sort of sign and demonstration of the luxury to be found inside at his house, he was throwing down in front of the doors feathers from birds plucked and slaughtered for a celebration.