The longest word you can spell without repeating a letter:
uncopyrightable.
The longest word with just one vowel:
strengths
The only English word with a triple letter:
goddessship
The word with the longest definition in most dictionaries: set
The shortest -ology (study of) word:
oology (the study of eggs.)
Of is the only word in which an "f" is pronounced like a "v".