Are there any English words with 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

= a space continuum = a continuous sequence

= a continuous sequence residuum = a chemical residue

= a chemical residue menstruum = the matter discharged during menstruation

= the matter discharged during menstruation triduum = a three-day period of religious observance in the Catholic Church

= a three-day period of religious observance in the Catholic Church duumvir = each of a pair of magistrates holding joint office in ancient Rome

= 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)

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

See other Vocabulary Questions.

Take a look at: Are there any English words containing the same letter three times in a row?