inch [OE] The inch and the *ounce have the same ultimate origin, both going back to Latin uncia ‘twelfth part’. The observation give someone an inch and they will take a mile dates from the mid 16th century. Originally people often took an ell rather than a mile (an ell is an old measure equal to just over a metre, used especially for cloth). The inch [ME] in the name of some Scottish islands, such as Inchcolm, is a completely different word, deriving from Scottish Gaelic innis ‘island, land by a river’.