What we call a “yard” was, in Old English, a “geard.” It was pronounced about the same way, but the word did something unusual during the transition to modern English: it split into two words, with “yard” keeping the Old English “g” sound that’s more like a “y,” but in the other (“garth”) the “g” letter remained, and adopted the “g” sound like in “ground.” Not only that, but the two words meant pretty much the same thing.
“Yard” is familiar today, and if you go back a ways (or go to some places in England), “garth” was just as common. A “garth” was any enclosed area like a yard (with a fence, I suppose), a garden, or a courtyard. There were quite a few specific kinds of “garth”, including apple-garth, barn-garth, cloister-garth, field-garth, and the redundant-sounding garden-garth.
Garden-garth sounds redundant because “garden” probably came from the same source as “garth” and “yard.” So really a garden-garth is a garden-garden, or possibly a yard-yard. And of course “yard” was used in much the same combinations; even today “churchyard” and “graveyard” are still used. And a “vineyard” is familiar as the place you grow grape vines to make wine.
There’s another kind of “yard” too; it’s a long stick-like thing that holds the bottom of the sail on a sailing ship. The reason that device is called a “yard” is that this version of “yard” originally meant any sort of stick, from the branch of a tree to a walking stick. The “stick” sort of yard also comes from Old English, from a word that’s confusingly close to “geard:” “gierd.” I suppose if you were fluent in Old English you wouldn’t be any more confused than we are today between “there” and “they’re.” Although come to think of it, we do get pretty confused about those words…
In any case, the kind of a yard that’s a stick might often be found within the kind of a yard that’s a garth, lending yet another bit of redundancy to the whole situation. Not to mention a “yardstick,” which you use to measure length in units of three feet at a time. The “yard” that’s three feet long started out as any sort of stick you’d use to measure things. Centuries before a “yard” was a standardized length, a “yard” was whatever stick you kept in your carpentry or dressmaking shop to measure things. You called it a yard, of course, because it was just a stick, not because of how long it was. So now, just when we think we’ve gotten all fancy and have standardized “yardsticks,” what we’re acting so modern and superior about is just a “stickstick,” just like one we could go grab from our “yardyard”.
You have to be a little bit careful in ordering things “by the yard,” though, because while a “yard of linen” is a fairly small amount, a “yard of concrete” is a cubic yard and quite a lot, and a “yard of land” is about thirty acres — which is enough to contain quite number of yards (or yardyards). Except of course that a “yard of land” is also the much smaller area about a quarter of an acre, depending on where and when you’re talking about it. The price also depends on where and when you are, so sometimes the price for a yard might be a yard — “yard” is also a slang term for a thousand dollars.
Maybe with all the yards and yards of kinds of yard, a little redundancy makes sense. After all, if you’re confused about what “yard” means, maybe “yardyard” would make it clearer whether you’re talking about a geard or a gierd. Or…well…not?