The rod is a unit of length in the imperial and US sytem and uses the symbol rod.
A rod (or perch, pole, lug) is equal to 16.5 feet or 5.5 yards.
It is a building surveyor's tool for measuring distance and is particularly useful as multiples of this unit can make up an exact acre. A perfect acre is a rectangle with edges 660 feet and 66 feet - which is 40 rods by 4 rods; i.e. 1 acre = 160 square rods.
The yard is a unit of length in the imperial and US system and uses the symbol yd.
A yard is equal to 3 ft or 36 inches. There is 0.9144 m in a yard. There are 1760 yards in a mile.
Derived from the Old English 'gyrd' or 'gerd', the yard was first defined in the late 1600s laws of Ine of Wessex where a "yard of land" (yardland) was an old unit of tax assessment by the government.
The yard was the original standard adpoted by early English leaders and was apparently used in length by the Saxon race and represented the breadth of the chest of a man. After a relative hiatus, Queen Elizabeth reintroduced the yard as the English standard of measure, and it still survives in many 2nd generation conversations today.