The inch is a unit of length in the imperial unit system with the symbol in.
There are 12 inches in a foot and 3 feet in a yard. Therefore there are 36 inches in a yard. There are exactly 2.54 centimetres in an inch.
Borrowed from the Latin 'uncia' - the English word 'inch', the origination of the word came from the Old English word for 'ounce' which was related to the Roman phrase for "one twelfth".
The inch is still a commonly used unit in the UK, USA and Canada - and is also still used in the production of electronic equipment, still very evident in the measuring of monitor and screen sizing.
The ell is a unit of length and originates from historic England and uses the symbol ell.
The ell usually measured 45in or 1.143m but was origally a "cubit" - which was the length from your elbow to the tip of your fingers and literally translated from the word "arm". It was mostly used in the tailoring world when buying and selling textiles.
Although now obsolete, the word "ell" still survives in the English word "elbow".