Spanish and Portuguese names:

It was also common for surnames originating from Castile and Álava to have the form "(patronymic) de placename". Hence for José Ignacio López de Arriortúa, "López de Arriortúa" is just one surname. This can cause confusion as both "López" and "de Arriortúa" can be found as single surnames. In Spain, unlike in neighboring France, the prefix "de" (meaning "of") on a surname does not typically indicate noble origin. It may be introduced just to mark a surname that can be misunderstood as a forename. Thus, Luis de Miguel Pérez marks that his forename is just Luis, not Luis Miguel. In short forms, the de may be included (Hernando de Soto is known as "de Soto") or not (Felipe de Borbón is a "Borbón", not a "de Borbón").

In Spanish, most surnames ending in "-ez" originated as patronymics. Thus "López" originally meant "son of Lope", "Fernández" meant "son of Fernando", etc. Other common examples of this are "Hernández" (from Hernando, a variant of "Ferdinand" / "Fernando"), "Rodríguez" (from "Rodrigo"), "Sánchez" (from "Sancho"), "Martínez" (from "Martín"), and "Álvarez" (from "Álvaro"). "Cortez" (e.g. Alberto Cortez), however, is a variant of "Cortés" (e.g. "Hernán Cortés").

After the recognition of co-official languages in Spain, the law allowed the translation or respelling of names to the official languages.

In 1849, the Spanish admnistration of the Philippines commanded every Filipino to take a Spanish surname from an approved list. Because of this, a Spanish surname does not necessarily imply any Spanish ancestry among all Filipinos.

Number of names

The official records keep at most two forenames and two surnames per person. However, people can be baptized with more than two forenames, which is a frequent practice among the royalty.

People can also keep track of more than two surnames. This is more frequent in the Basque Country. For example, the founder of Basque nationalism, Sabino Arana, demanded several Basque surnames from his followers to certify that there was no admixture of "foreigners" in their ancestry.