For his 1755 "Dictionary of the English Language", he wrote definitions for more than 40,000 words
[DOC] [TLE] Samuel Johnson's Dictionary of the English Language [PAR] First published in 1755, Johnson's work is one of the most famous and important 
... and lists 40,000 words, each defined in detail and illustrated with quotations ... 
which appeared in 1538; it's actually an English-Latin dictionary, he writes, 
adding ... the "hard words", Johnson opened his pages to words people actually 
used.