'XL' originates from the Latin numeral system, where 'X' represents '10' and 'L' represents '50', together symbolizing '40' in Roman numerals, but in modern usage, it stands for 'extra large'.

'XL' was adopted into modern English as a shorthand for 'extra large', especially in clothing sizes.

Initially, 'XL' was a Roman numeral for '40', but over time it evolved into its current meaning of 'extra large'.