Here's the breakdown:
* Old English: The earliest known form of the word is "sċeal", meaning "shell" or "husk". This is likely where the connection to the layered, flaky nature of shale rock originates.
* Middle English: The word evolved to "shale", retaining the sense of "shell" or "thin layer".
* Modern English: We use "shale" today to refer to the fine-grained sedimentary rock, usually composed of clay and silt.
Interestingly:
* The word "shale" is related to the German word "Schale", which means "bowl" or "shell". This reinforces the connection to the shape and structure of shale.
* The word "shell" itself also derives from the same Germanic root.
So, the next time you see a piece of shale, remember that its name reflects its physical characteristics – layered and thin, like a shell!