This is a list of surnames in which the categories include uncertain etymology.
AcquaroneItalian Meaning uncertain, possibly from a place name or an occupation derived from Italian acqua "water".
AriasSpanish Possibly derived from a medieval given name of Germanic origin.
ÁvilaSpanish From the name of the city of Ávila in Spain. It is of uncertain meaning, possibly of Punic or Celtic origin.
AyalaSpanish From the name of the town of Ayala (called Aiara in Basque) in Álava, Spain. It might be derived from Basque aiher "slope" or alha "pasture".
BoyleIrish From Irish Ó Baoighill meaning "descendant of Baoigheall". The meaning of the given name Baoigheall is uncertain, but it is thought to be connected to Irish geall meaning "pledge".
BruceScottish Possibly from the name of the town of Brix in Normandy, which is of unknown meaning. It was brought to Scotland in the 12th century by the Anglo-Norman baron Robert de Brus. It was later borne by his descendant Robert the Bruce, a hero of the 14th century who achieved independence from England and became the king of Scotland.
CadenIrish From Irish Mac Cadáin meaning "descendant of Cadán", a given name of unknown meaning.
CamachoSpanish, Portuguese Meaning unknown, possibly related to the Celtic root *kambos meaning "crooked, twisted".
CarmodyIrish Anglicized form of Irish Ó Cearmada meaning "descendant of Cearmaid", a Gaelic given name.
CarsonScottish Meaning uncertain, possibly from the town of Courson in Normandy.
CochraneScottish From the name of a place in Renfrewshire, Scotland. Its origin is uncertain.
DenzilEnglish From the place name Denzell, a manor in Cornwall, which is of unknown meaning.
GarcíaSpanish From a medieval given name of unknown meaning, possibly related to the Basque word hartz meaning "bear". This is the most common surname in Spain.
McCauleyIrish, Scottish Anglicized form of Gaelic Mac Amhalghaidh or Mac Amhalghadha meaning "son of Amhalghaidh". The given name Amhalghaidh, from Old Irish Amalgaid, is of uncertain meaning.
McElligottIrish Anglicized form of the Irish Gaelic name Mac Uileagóid meaning "son of Uileagóid", a diminutive of Uilleag.
MetharomThai Possibly refers to a place or institute of learning or where knowledge is provided.
MontoyaSpanish From the name of a village in the province of Álava in Spain. It is possibly of Basque origin, or possibly from Latin mons "mountain, hill".
MuñozSpanish Patronymic derived from the medieval Spanish given name Muño, from Latin Munnius, possibly of Germanic origin.
Ó ComhraidheIrish Means "descendant of Comhraidhe", in which the given name Comhraidhe is of unknown meaning.
PaviaItalian From the name of the city of Pavia in Lombardy, Italy. It is of unknown meaning.
QuesadaSpanish Habitational name from Quesada, a place in Jaén in southern Spain. The place name is of uncertain derivation; it could be connected to Old Spanish requexada meaning "corner, tight spot".
RavennaItalian From the name of the city of Ravenna in northern Italy, which is of uncertain origin, possibly Etruscan.
SappingtonEnglish Possibly from the city of Sapperton, England, derived from Old English sapere meaning "soap maker" and tun meaning "enclosure, yard, town".
SavonaItalian From the name of the city of Savona in northern Italy, called Savo by the Romans, of uncertain meaning.
SigourneyEnglish From the name of the commune of Sigournais in western France, called Segurniacum in medieval Latin, itself of unknown meaning.
TavaresPortuguese From any of the numerous places in Portugal called Tavares, likely of pre-Roman origin.
TiraboschiItalian Possibly of Lombardic origin meaning "shepherd" (from Old German tior "animal" and bursa "boy"). This surname is typical of Lombardy.
UreñaSpanish Probably derived from the name of Urueña, a town in the province of Valladolid, Spain, which is of unknown meaning.