"Judas" is a song by American recording artist Lady Gaga, from her second studio album Born This Way (2011). It was released by Interscope Records on April 15, 2011, four days ahead of its scheduled release. Written and produced by Lady Gaga and RedOne, "Judas" is a electro house and dance song about a woman in love with a man who betrayed her. It embodies the incidents that have haunted Gaga in the past, and its core meaning refers to the negative parts of her life that she can't escape. Gaga has further explained that the song was also about honoring one's inner darkness in order to bring oneself into the light. The artwork for the single was designed by Gaga in Microsoft Word. In spite of a polarizing impact on several religious groups, the song was generally well received by critics, who likened the song to "Bad Romance" with some noting it should have should have been the album's lead single.

The song has a similar sound to Gaga's previous RedOne-produced tracks, including "Poker Face", "LoveGame", "Bad Romance", and "Alejandro". It contains three distinct hooks and a house-influenced break down. Gaga explained that the lines spoken during the breakdown talk about her as beyond redemption, regarding the traditional views of what a woman should be. Critics noted similarity between "Judas" and "Bad Romance", but praised the musical production of the song. "Judas" initially had a strong sales opening, but was less successful commercially in comparison to Gaga's previous singles. The song reached the top ten of the charts in most major music markets, and also reached the top of the charts in South Korea.

Judas (Greek: Ιούδας) is the anglicized Greek rendering of the Hebrew name Yehudah (Hebrew: יְהוּדָה), also rendered in English as Judah.

By Hellenitic times Judah (Heb. Yehudah) had become a common first name among Jews (whose collective name - "Yehudim" יהודים in Hebrew - is also derived from the same source) and, in the English form Judah, has remained so up to the present. Specifically, it was a common first name in the first century AD Jewish society inside which Christianity came into being.

In music, a song is a composition for voice or voices, performed by singing. A song may be accompanied by musical instruments, or it may be unaccompanied, as in the case of a cappella songs. The lyrics (words) of songs are typically of a poetic, rhyming nature, though they may be religious verses or free prose.

A song may be for a solo singer, a duet, trio, or larger ensemble involving more voices. Songs with more than one voice to a part are considered choral works. Songs can be broadly divided into many different forms, depending on the criteria used. One division is between "art songs", "pop songs", and "folk songs". Other common methods of classification are by purpose (sacred vs secular), by style (dance, ballad, Lied, etc.), or by time of origin (Renaissance, Contemporary, etc.).

A song is a piece of music for accompanied or unaccompanied voice or voices or, "the act or art of singing," but the term is generally not used for large vocal forms including opera and oratorio. However, the term is, "often found in various figurative and transferred sense (e.g. for the lyrical second subject of a sonata...)." The noun "song" has the same etymological root as the verb "to sing" and the Oxford English Dictionary (OED) defines the word to mean "that which is sung" or "a musical composition suggestive of song." The OED also defines the word to mean "a poem" or "the musical phrases uttered by some birds, whales, and insects, typically forming a recognizable and repeated sequence and used chiefly for territorial defence or for attracting mates."