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It's an illustration that is not bound into a book but is glued in on one edge. The plate is the illustration.
Long ago, when printing processed could only accommodate line drawings, if any, a photograph or color illustration might be tipped in. A book might have only one, in the front, or perhaps a very small number, and they were considered special.
First answer by SapphireMoon. Last edit by SapphireMoon. Contributor trust: 392 [recommend contributor]. Question popularity: 7 [recommend question]





