One of the oldest documents preserved at the Real Academia de la Historia in Madrid presents only this phrase as the poem's title: Hic incipiunt gesta Roderici Campi Docti, which means "Here begin the deeds of Rodrigo the Campeador."[7] Its current title is a 19th-century proposal by Ramón Menéndez Pidal since its original title is unknown. Some merely call the poem El Poema del Cid on the grounds that it is not a cantar but a poem made up of three cantares. The title has been translated into English as The Lay of the Cid and The Song of the Cid. Mio Cid is literally "My Cid", a term of endearment used by the narrator and by characters in the work.[4] The word Cid originates from Arabic sidi or sayyid (سيد), an honorific title similar to English Sir (in the medieval, courtly sense).
The commonly used title El Cantar de mio Cid means literally The Song of my Lord or The Poem of my Lord. As the original title of the poem is lost to history, this one was suggested by historian Ramón Menéndez Pidal. It is Old Spanish (old Castilian), adjusted to modern orthography. In modern Spanish the title might be rendered El Poema de mi Señor or El Poema de mi Jefe. The expression cantar (literally "to sing") was used to mean a chant or a song. The word Cid (Çid in old Spanish orthography), was a derivation of the dialectal Arabic word سيد sîdi or sayyid, which means lord or master. During the period the poem was written, Arabic was still a widely used and highly regarded language in Iberia (hence the fact that modern Spanish still contains many Arabic words). Çid was not a common word, though, in old Spanish and thus can be treated almost as a proper noun.
