Dictionary

The first New Oxford American Dictionary carried 'esquivalience', a word for 'the willful avoidance of official responsibilities'. An editor invented it as a trap for copyists. Dictionary.com copied it and got caught. Such planted fakes are called a 'mountweazel'.

In 1934, Webster's second edition printed 'dord', a Word that never existed. Defined as meaning density, it began as an editor's slip 'D or d' (D or d abbreviates density), misread as one word. The ghost entry sat in the Dictionary five years before anyone caught it: a 'ghost word'.