A nobiliary particle is used in a family name or surname in many Western cultures to signal the nobility of a family. The particle used varies depending on the country, language and period of time. This article is dedicated to explain how noble families of different countries identify themselves by using a nobiliary particle. However, in some languages the nobiliary particle is the same as a regular prepositional particle that was used in the creation of many surnames. In some countries it became customary to distinguish the nobiliary particle from the regular one by different spelling, although in other countries these conventions did not arise, occasionally resulting in ambiguity.

In France, the particle de precedes a nom de terre ("name of land") in many families of the French nobility (for example, Maximilien de Béthune). A few do not have this particle (for example, Pierre Séguier, Lord Chancellor of France). The particle can also be du ("of the" in the masculine form), d' (employed, in accordance with the rules of orthography, when the nom de terre begins with a vowel; for example, Ferdinand d'Orléans), or des ("of the" in the plural). In French, de indicates a link between the land and a person—either landlord or peasant.