I would never have imagined there was more than one word with two u’s.  There are a few!  Who knew??

What words in the English language contain two u’s in a row?

There are several English words containing two consecutive u’s. Most of them came into English from Latin:

vacuum = a space
continuum = a continuous sequence
residuum = a chemical residue
menstruum = the matter discharged during menstruation
triduum= a three-day period of religious observance in the Catholic Church
duumvir = each of a pair of magistrates holding joint office in ancient Rome
duumvirate = a coalition of two people having joint authority
All but the first two words on this list are quite rare, though, or are only likely to be encountered in specialist contexts. There are also a couple of other words containing two u’s in a row that have come into English from other languages:

muumuu = a loose dress of a kind traditionally worn in Hawaii (from Hawaiian)
Weltanschauung = the world view of a particular individual or group (from German)