The pica is a unit of length in the field of typography and uses the symbol pc.
There are 12 points in 1 pica. 1 pica represents approximately 1/6 of an inch.
Picas are expressed using numbers and a lower case p on software such as Adobe InDesign - for example 8p6 which would represent 8 picas and 6 points (or 8.5 picas).
The Pica is very useful in measuring and calculating the space needed to print letters and words on paper - for example when laying out books or magazine articles; the font lengths are quanitified by the number of characters per pica (cpp).
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.