15-letter words
atheroscleroses, atherosclerosis, electrophoresed, electrophoreses, electrophoresis
16-letter words
arterioscleroses
This twenty-one-letter word is the longest I could find:
anemometrographically
There are a couple of twenty-letter words as well:
electroencephalogram
microcrystallography
You cannot make any words using all of these letters. The longest word you can make is moo.
You cannot make any words with seven letters using these letters. The longest word you can make is honda.
There's no word using all the letters, here are the two longest words:tenchtenth
lowercased
The longest common English word you can make from the top line of your keyboard or qwertyuiop is typewriter (10 letters).The longest possible word is rupturewort, a type of plant (11 letters).The longest slang word using all letters only once is wipeout (7 letters). The longest formal words have six letters : equity, poetry, purity, pyrite, torque, troupe and qwerty (it means the kind of keyboard we are now using).
DETECTED
TYPEWRITER 10 letters
There is no word using all of the letters. The longest possible word is "BALANCE"
The longest word you can make using those letters once is "keyboard."
Using a 3-letter minimum, you can make over 1000 words with the letters carrot is bored. The longest word you can make is bioreactors.
The longest words you'll make out of those letters are camp, coma, comp, capo
The longest I could find, using both the Scrabble dictionary, and Webster's Second International, was seventeen letters: rhomborectangular