A diaconia was originally an establishment built near a church building, for the care of the poor and distribution of the church's charity in medieval Rome or Naples (the successor to the Roman grain supply system, often standing on the very sites of its stationes annonae). Examples included the sites of San Vito

Arch of Gallienus

The Arch of Gallienus is an ancient Roman arch in Rome, built in 262 on the site of the Porta Esquilina, the start of the via Labicana and via Tiburtina. It was built by a private citizen, the equestrian Marcus Aurelius Victor, and dedicated to the emperor Gallienus and his wife Cornelia...

, Santi Alessio e Bonifacio, and Sant'Agatha

Sant'Agata dei Goti

Sant'Agata dei Goti is a church in Rome, Italy, dedicated to the martyr Saint Agatha. It is currently the titular church assigned to Cardinal Raymond Leo Burke, currently Prefect of the Supreme Tribunal of the Apostolic Signatura.-History:...

 in Rome, San Gennaro

Cathedral of Naples

Naples Cathedral is a Roman Catholic cathedral, the main church of Naples, southern Italy, and the seat of the Archbishop of Naples. It is widely known as the Cattedrale di San Gennaro, in honour of Saint Januarius, the city's patron saint, but is actually dedicated to the Assumption of the...

 in Naples (headed by a deacon named John in the end of the ninth and the beginning of the tenth century.

The word has now come to mean the titular church of a Cardinal Deacon.

An alternative spelling, diakonia, is a Christian theological term from Greek that encompasses the call to serve the poor and oppressed. The terms deaconess

Deaconess

Deaconess is a non-clerical order in some Christian denominations which sees to the care of women in the community. That word comes from a Greek word diakonos as well as deacon, which means a servant or helper and occurs frequently in the Christian New Testament of the Bible. Deaconesses trace...

 and diaconate also come from the same root, which refers to the emphasis on service within those vocations.