|MadSci Network: Science History|
where did the terms inch, yard, foot come from? How were they derived?
First, we don't do your homework for you; you might try consulting a printed reference, like a dictionary. But this is a question of general interest.
I consulted a dictionary and came up with the following (though some of it I already knew).
A "foot" is pretty obvious; someone measured a standard human foot (the most common explanation is that it was the king's foot). My feet, for example, are slightly more than a foot long (I wear a size 13, but don't ask me where the shoe sizes come from!)
The word "inch" is ultimately (?) derived from the Latin uncio, meaing one-twelfth. After all, an inch is one-twelfth of a foot.
The word "yard" is derived from Anglo-Saxon and Middle English words meaning "a rod, a staff, a yard measure." The yard, like the foot and the inch, is a fairly ancient unit. I gather that it was originally derived from the distance from the base of a man's neck to the tips of his fingers, but I don't know that for certain. One could just as easily say that a rod used for driving cattle might be about three feet long.
Incidentally, the "rod" mentioned is not the same as the "rod" as a unit of length: the linear rod is 5½ yards, and the word is derived from the Middle English for "pole." Thus do words change meanings over the years...
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