Yard
3 of the 7 encyclopedias on this shelf carry an entry for Yard. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
the English linear measure equivalent to three feet or thirty-six inches. The word is akin to good and yerd, meaning a rod or stick, but whether the stick was originally the length of a foot-pace or of a man's arm is not known. Custom determines the length of the yard reasonably well. It has been defined by statute as the distance between two marks on a metal bar deposited with the English keeper of weights and measures. The yard is by no means a scientific measure. If this metal rod were destroyed there is no way of reproducing it exactly. The United States government has abandoned the English yard for a yard based on the scientific meter. It has been found that the American yard is slightly longer than the English standard.
Collier's New Encyclopedia (1921)
in ordinary language, the British and American standard of measure, being equal to 3 feet or 36 inches. As a cloth measure the yard is divided into four quarters 16 nails. A square yard contains 9 square feet, and a cubic yard 27 cubic feet. A yard=91,4382 centimeters, a square yard=8,361.13 square centimeters, and a cubic yard= 764,535 cubic centimeters. As a nautical term, a spar slung from a mast and serving to extend a sail. Yards are either square, lateen, or lug sail. Yards for square sails are suspended across the mast at right angles, and are of a cylindrical form, tapering from the middle, which is termed the slings, toward the extremities, which are called the yard arms.
The Encyclopedia of Founding (1892)
The standard measure of linear dimension. It is subdivided into feet and inches. Three feet are contained in one yard, and each foot = 12 inches.