Although more usually used to describe the common earthworm, the English language word "worm" derives from Old Norse orm and Anglo-Saxon 'wyrm, meaning "serpent" or "dragon". The synonymous usage of worm and dragon in English lessened during the following centuries. Samuel Johnson's dictionary drew a distinction between worms and dragons (while retaining the word serpent as a definition of worm) and the last synonymous usage of worm and dragon as noted in the Oxford English Dictionary dates to the 17th century.