wafer

A light, thin, flat biscuit/cookie.

I was at the Mathematical School, where the Maſter taught his Pupils after a Method ſcarce imaginable to us in Europe. The Propoſition and Demonſtration were fairly written on a thin Wafer, with Ink compoſed of a Cephalick Tincture. This the Student was to ſwallow upon a faſting Stomach, and for three days following eat nothing but Bread and Water. As the Wafer digeſted, the Tincture mounted to his Brain, bearing the Propoſition along with it.

A thin disk of consecrated unleavened bread used in communion.

A soft disk originally made of flour, and later of gelatin or a similar substance, used to seal letters, attach papers etc.

The house supplied him with a wafer for his present purpose, with which, having sealed his letter, he returned hastily towards the brook side, in order to search for the things which he had there lost.

A thin disk of silicon or other semiconductor on which an electronic circuit is produced.

To seal or fasten with a wafer.

[M]y Father, who knew he was well, wafered the paragraph upon a sheet of paper, and sent to his Lodgings.

[T]he beginning of de Barral's end became manifest to the public in the shape of a half-sheet of note-paper wafered by the four corners on the closed door […].