thumbtack
The English word BOOKKEEPING or BOOKKEEPER has three sets of consecutive double letters. SUBBOOKKEEPER is the only word with four sets of consecutive double letters, although these words should be hyphenated.
There are many words that have 3 consecutive letters in them. define erstwhile stump
Define.Nope.First.Stupid.
The following words have three consecutive sets of double letters:bookkeeperbookkeepersbookkeeping
Words like those are rare. In Scrabble, the word 'zzz', 'zzzs', and 'brrr' are valid.
absent
committee
"Obsequious".
bookkeeper
bookkeeper
Mississippi
borrow