Agnes is a female given name

Given name

A given name, in Western contexts often referred to as a first name, is a personal name that specifies and differentiates between members of a group of individuals, especially in a family, all of whose members usually share the same family name...

, which derives from the Greek name Ἁγνὴ hagnē, meaning "pure" or "holy". The Latinized form of the Greek name is Hagnes, the feminine form of Αγνός Hagnos, meaning "chaste" or "sacred". The name passed to Italian

Italian language

Italian is a Romance language spoken mainly in Europe: Italy, Switzerland, San Marino, Vatican City, by minorities in Malta, Monaco, Croatia, Slovenia, France, Libya, Eritrea, and Somalia, and by immigrant communities in the Americas and Australia...

 as Agnese, to Portuguese

Portuguese language

Portuguese is a Romance language that arose in the medieval Kingdom of Galicia, nowadays Galicia and Northern Portugal. The southern part of the Kingdom of Galicia became independent as the County of Portugal in 1095...

 as Inês, and to Spanish

Spanish language

Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...

, as Inés.

It was the name of a popular Christian saint, Saint Agnes of Rome, a fact which encouraged the wide use of the name.