"Cornerstone" is a song by the English indie rock band Arctic Monkeys, released as the second single from their third album Humbug. It was released on 16 November 2009. Like the previous single "Crying Lightning", the vinyl was made available in Oxfam shops.Alex Turner told Uncut magazine that he wrote this song, "one morning, quite quickly." He added: "There's something to be said for writing in the morning. At other points in the day you're a bit more defensive. I saw it as a challenge to write something in a major key, but that wasn't cheesy." It was originally written in the key of A Major. In October 2013 it was sampled by the rapper Dom Kennedy for the song "Pleeze" on his album Get Home Safely.
The music video for the single debuted on Channel 4 in the UK on 15 October 2009.
The music video, directed by Richard Ayoade, who worked on the videos of "Fluorescent Adolescent", "Crying Lightning" and their "At the Apollo" DVD, shows frontman Alex Turner singing the song alone in a white room during the whole video. The other members of the band (Jamie Cook, Matt Helders and Nick O'Malley) are not present in the video.
Being released as an EP in Oxfam shops, the single charted at number 94 in the UK charts and charted at 7 on the UK indie charts. It also debuted at number 7 on the Soundscan singles charts for sales in Canada. One of the single's B-sides, "Sketchead", peaked at number 80 on the UK Single Charts, fourteen places higher than "Cornerstone"'s peak position.