string [OE] The Germanic root of string is related to strong [OE], and in early use it could refer to a rope or cord of any thickness. If you have many strings to your bow [E16th] you have a wide range of resources, just as an archer ought to have spare strings. To have someone on a string is 16th-century from a puppeteer manipulating a puppet by its strings. An opportunity or offer with no strings attached [L19th] it is based on a US use of string meaning ‘a limitation or condition’.