It is used in English for certain Benedictine (including some communities which follow the Rule of St. Benedict) and Carthusian monks, and for members of certain communities of Canons Regular. Examples include Benedictine monks of the English Benedictine Congregation (e.g. Dom John Chapman, late Abbot of Downside). The equivalent title for a nun is "Dame" (e.g. Dame Laurentia McLachlan, late Abbess of Stanbrook, or Dame Felicitas Corrigan, author).
In Portugal and Brazil, Dom (pronounced: [ˈdõ]) is used for certain hierarchs of the Roman Catholic Church and for laymen who belong to the royal and imperial families (for example the House of Aviz in Portugal and the House of Braganza in Portugal and Brazil). It was also accorded to members of families of the titled Portuguese nobility. Unless ennobling letters patent specifically authorised its use, Dom was not attributed to members of Portugal's untitled nobility: Since hereditary titles in Portugal descended according to primogeniture, the right to the style of Dom was the only apparent distinction between cadets of titled families and members of untitled noble families. Dom has historically been used on occasions in French, as an honorific for Benedictine monks, such as the famous Dom Pérignon. The feminine form, Dona, is a common honorific reserved for women, such as the First Lady of Brazil. In Portugal the feminine version of the honorific is more broadly attributed to women than Dom is to men.
- Angus Stevenson, ed. (2007). Shorter Oxford English Dictionary. Volume 1, A – M (Sixth ed.). Oxford, UK: Oxford University Press. p. 737. ISBN 978-0-19-920687-2.
- Tourtchine, Jean-Fred (September 1987). "Le Royaume de Portugal - Empire du Brésil". Cercle d'Études des Dynasties Royales Européennes (CEDRE):. III: 103. ISSN 0764-4426.