Etymological wanderings: deckled edition
My libray was recently asked to scan and digitize an old law book for another library in the state. When we received the book, I had to carefully examine it to see what scanner we should use, taking into account the book's size and paper quality.
The pages of the book had a somewhat ragged, uneven edge, which led my coworker to describe them as "rag paper." I volunteered that the technical term is actually a "deckled edge." (To make matters more confusing "rag paper" is also a technical term, but it refers to paper with a high cotton content ("rag content"), due to cotton rags being added to the paper pulp.)
My coworker asked where the word "deckle" came from, and I realized that I didn't know. (But if you know me, you know I can't let that state of things last for very long.) The German word "decke" means "cover." It's diminutive form is "deckel," which came to refer to a cover placed over a screen when making paper, to force the pulp to be confined to a certain space. Eventually, the spelling changed slightly, and the word "deckle" came to refer to the ragged, untrimmed edge of a sheet of handmade paper.
This reminded me of another term which has the same German root. "Gedeckt" (lit. "covered") refers to a certain type of organ pipe which has a cover on top, instead of being open to the air. Covering the top makes the pipe sound an octave lower, although there are tradeoffs in terms of overtones.
Lastly, the English word "deck" also comes from the same German root, because the deck of a boat can be thought of as a cover for its cargo. Other types of decks are named by extension from boat decks.