The primordial monolingual English dictionary; it defined 2,543 words and was written by the English schoolmaster Robert Cawdrey.
1. Published in London in 1604, the only surviving copy is at Oxford's Bodleian Library; however, you can peruse a digital copy of it by clicking here.
Example - Some example definitions:
adamantine, as hard as Diamont
addict, giuen too, appointed too
Syntaxe, construction and order of words.