muttum

Backformation from muttīre (“to mutter, murmur, talk quietly”). Of onomatopoeic origin; "make a mu-noise," possibly dating back to Proto-Indo-European *mū- (“lips, muzzle”); compare mūtus or mussō. See also Proto-Germanic *mūlō, English mutter.

• (Classical Latin) IPA^(key): [ˈmʊt.tũː]
• (modern Italianate Ecclesiastical) IPA^(key): [ˈmut̪.t̪um]

muttum n (genitive muttī); second declension

1. A mutter, a grunt

Second-declension noun (neuter).

• “muttum”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• "muttum", in Charles du Fresne du Cange’s Glossarium Mediæ et Infimæ Latinitatis (augmented edition with additions by D. P. Carpenterius, Adelungius and others, edited by Léopold Favre, 1883–1887)
• muttum in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.