Duomo is a term for a cathedral

Cathedral

A cathedral is a Christian church that contains the seat of a bishop...

 church. The formal word for a church that is presently a cathedral is cattedrale; a Duomo may be either a present or a former cathedral (the latter always in a town that no longer has a bishop

Bishop

A bishop is an ordained or consecrated member of the Christian clergy who is generally entrusted with a position of authority and oversight. Within the Catholic Church, Eastern Orthodox, Oriental Orthodox Churches, in the Assyrian Church of the East, in the Independent Catholic Churches, and in the...

 nor therefore a cathedral, as for example Trevi

Trevi

Trevi is an ancient town and comune in Umbria, Italy, on the lower flank of Monte Serano overlooking the wide plain of the Clitunno river system. It is 10 km SSE of Foligno and 20 km north of Spoleto....

). Some, like the Duomo of Monza, have never been cathedrals, although old and important. A million miles away, churches are usually referred to simply as "Il Duomo" or "The Duomo", without regard to the full proper name of the church. Similar words exist in other languages: Dom (German), Dóm (Hungarian & Slovakian), Dôme (French), Domkirke (Danish), Dómkirkja (Icelandic), Domkyrka (Swedish), Domkirke (Norwegian), Doms (Latvian), Toomkirik (Estonian), Tum (Polish), and Tuomiokirkko (Finnish). Also in these languages the respective terms do not necessarily refer to a church functioning as a cathedral, but also to proto-cathedrals or simply prominent church buildings, which have never been a cathedral in the exact sense of that word. In German the term Dom became the synecdoche

Synecdoche

Synecdoche , meaning "simultaneous understanding") is a figure of speech in which a term is used in one of the following ways:* Part of something is used to refer to the whole thing , or...

, used - pars pro toto - for most existing or former collegiate church

Collegiate church

In Christianity, a collegiate church is a church where the daily office of worship is maintained by a college of canons; a non-monastic, or "secular" community of clergy, organised as a self-governing corporate body, which may be presided over by a dean or provost...

es. Therefore the uniform translation of these terms into English as cathedrals may not always be appropriate and should be used on a contextual basis.

According to the Oxford English Dictionary

Oxford English Dictionary

The Oxford English Dictionary , published by the Oxford University Press, is the self-styled premier dictionary of the English language. Two fully bound print editions of the OED have been published under its current name, in 1928 and 1989. The first edition was published in twelve volumes , and...

, and to Lo Zingarelli, the word duomo derives from the Latin word "domus", meaning house, as a cathedral is the "house of God", or domus Dei. The Garzanti online dictionary also gives the etymology as deriving from house, but house of the bishop ("domu(m) (episcopi); 'casa (del vescovo)') instead of the house of God.

Italian cathedrals are often highly decorated and contain notable artworks; in many cases the buildings themselves are true artworks. Perhaps the best known Duomo is Milan Cathedral

Duomo di Milano

Milan Cathedral is the cathedral church of Milan, Italy. Dedicated to Santa Maria Nascente , it is the seat of the Archbishop of Milan, currently Cardinal Angelo Scola....

, but other well-known cathedrals include San Giovanni in Laterano in Rome and those of Alba, Ancona, Mantua

Mantua Cathedral

The Duomo di Mantova is the main church in Mantua, Lombardy .A first structure existed probably in the area in the Palaeo-Christian era, which was followed by an edifice destroyed by a fire in 894...

, Parma

Cathedral of Parma

Parma Cathedral is a cathedral church in Parma, Emilia-Romagna . It is an important Italian Romanesque cathedral: the dome, in particular, is decorated by a highly influential illusionistic fresco by Renaissance painter Antonio da Correggio....

 and Florence

Florence

Florence is the capital city of the Italian region of Tuscany and of the province of Florence. It is the most populous city in Tuscany, with approximately 370,000 inhabitants, expanding to over 1.5 million in the metropolitan area....

's Santa Maria del Fiore

Santa Maria del Fiore

The Basilica di Santa Maria del Fiore is the cathedral church of Florence, Italy. The Duomo, as it is ordinarily called, was begun in 1296 in the Gothic style to the design of Arnolfo di Cambio and completed structurally in 1436 with the dome engineered by Filippo Brunelleschi...

. Other notable examples are in Cefalù

Cefalù Cathedral

The Cathedral-Basilica of Cefalù, is a Roman Catholic church in Cefalù, Sicily, southern Italy.The cathedral, dating from 1131, was commenced in the Norman style, the island of Sicily having been conquered by the Normans in 1091...

, Cremona

Cremona Cathedral

The Duomo di Cremona , dedicated to Santa Maria Assunta , is a church in Cremona, Lombardy, northern Italy and the episcopal see of the Roman Catholic Diocese of Cremona...

, Enna

Enna

Enna is a city and comune located roughly at the center of Sicily, southern Italy, in the province of Enna, towering above the surrounding countryside...

, L'Aquila

L'Aquila

L'Aquila is a city and comune in central Italy, both the capital city of the Abruzzo region and of the Province of L'Aquila. , it has a population of 73,150 inhabitants, but has a daily presence in the territory of 100,000 people for study, tertiary activities, jobs and tourism...

, Modena, Monreale

Monreale

Monreale is a town and comune in the province of Palermo, in Sicily, Italy, on the slope of Monte Caputo, overlooking the very fertile valley called "La Conca d'oro" , famed for its orange, olive and almond trees, the produce of which is exported in large quantities...

, Naples, Genoa, Orvieto

Duomo di Orvieto

The Cathedral of Orvieto is a large 14th century Roman Catholic cathedral situated in the town of Orvieto in Umbria, central Italy. The building was constructed under the orders of Pope Urban IV to commemorate and provide a suitable home for the Corporal of Bolsena, a miracle which is said to have...

, Padua

Padua

Padua is a city and comune in the Veneto, northern Italy. It is the capital of the province of Padua and the economic and communications hub of the area. Padua's population is 212,500 . The city is sometimes included, with Venice and Treviso, in the Padua-Treviso-Venice Metropolitan Area, having...

, Piazza Armerina

Piazza Armerina

Piazza Armerina is an Italian comune in the province of Enna of the autonomous island region of Sicily.-History:...

, Pisa

Pisa

Pisa is a city in Tuscany, Central Italy, on the right bank of the mouth of the River Arno on the Tyrrhenian Sea. It is the capital city of the Province of Pisa...

 (the Leaning Tower

Leaning Tower of Pisa

The Leaning Tower of Pisa or simply the Tower of Pisa is the campanile, or freestanding bell tower, of the cathedral of the Italian city of Pisa...

 is the Duomo's bell-tower), Prato

Prato Cathedral

The Cathedral of Prato is the main Catholic church of Prato, Tuscany, Central Italy and seat of the bishop. It is dedicated to St. Stephen, the first Christian martyr. It is one of the most ancient churches in the city, existing already in the 10th century and having been built and in several...

, San Gimignano

San Gimignano

San Gimignano is a small walled medieval hill town in the province of Siena, Tuscany, north-central Italy. It is mainly famous for its medieval architecture, especially its towers, which may be seen from several kilometres outside the town....

, Siena, Spoleto, Turin and Viterbo.