inch: [OE] Inch and ounce both mean etymologically ‘one twelfth’, but while this ancestral sense has largely been lost sight of in the case of ounce, for inch it remains in force. The words’ common ancestor is Latin uncia, a term for a ‘twelfth part’ derived from unus ‘one’. This was borrowed into prehistoric Germanic as *ungkja, but it has not survived in any other Germanic language but English. => one, ounce