Longest Word in the English Language Dictionary
At 45 letters
Pneumonoultramicroscopicsilicovolcanoconiosis is the longest non-scientific/place-name word in any
English language dictionary.
The word appears in the 1936 Supplement to
OED1, the
OED2, the addendum to
W2 (spelled -koniosis),
W3 (spelled -coniosis),
RHUD2, and
Chambers.
The
OED2 has:
Click here for links to the English Language.