"Green Light" is a song by New Zealand singer-songwriter Lorde, released on 2 March 2017 as the lead single from her second studio album Melodrama (2017). It was written and produced by Lorde and Jack Antonoff, with additional writing by Joel Little and production assistance from Frank Dukes, and was released to radio stations by Universal. Musically, "Green Light" is an electropop, dance-pop, and post-disco song. The lyrics use a "green light" as a traffic light metaphor that gives Lorde permission to move on with her life after a breakup.
In an interview with Tavi Gevinson's podcast Rookie, she revealed that the song's piano part was inspired when she went to a Florence and the Machine concert with Jack Antonoff. The singer's pianist made "big, jangly" piano movements, where "the physicality of that movement [...] became the way Jack played" that part in the song. Lorde also revealed that her sound-to-color synesthesia played a significant factor in the song's title, saying that a "swirling combo of high school and recent and private and public memories" helped to make the title represent a green traffic light. She announced the release of the single and its music video on Twitter on 2 March 2017.
The track begins with her singing solo with a lone piano playing "slow, steady" power chords consisting of a root note and the fifth above. Subsequently, in the first of the song's two pre-choruses, a "throbbing beat" plays amid "tongue-twisting lyrics, eerie background vocals, and bubbling electronic effects." In the second pre-chorus, a "cheery, upbeat piano loop and a kick drum" accompany Lorde as she sings about an "uneasy new reality." Here, the titular metaphor comes in the form of a hook: "I'm waiting for it, that green light, I want it," leading reviewers to interpret the "green light" as a street signal that gives the singer permission to move on into the future.
"Green Light" received widespread acclaim from music critics upon its release, with many publications placing the song in their respective year-end lists. Jason Lipshutz of Billboard commended the track, highlighting the singer's songwriting in particular, saying, "Lorde makes a good case that her songwriting, above all else, is her strongest asset." In his favorable A review, Nolan Feeney of Entertainment Weekly praised the song's production, stating that it sounded "like nothing else on the radio or in your Spotify playlists." Hugh McIntyre of Forbes noted Lorde's transition from her previous melancholia production to a "more upbeat feeling". He also praised the singer for being able to create a dance song "without caving into any trend in pop or dance".
The video starts with a close up shot of Lorde looking at herself in a mirror in a public restroom. In the next scene, she is dancing slowly in a club, with the silhouettes of other partygoers and flashing lights around her. She then exits the club at night, dressed in a hot pink Giorgio di Sant'Angelo tie-back mini dress and white Adidas Originals superstars, and steps inside a black Uber. Lorde opens the passenger window and places her head partly outside the window, letting the wind rush by her as the Uber drives through the streets of Los Angeles. In the following scene, she is seen dancing on top of the Uber while red lights shine on her.
Walking the streets alone, Lorde plays a Walkman, puts on earphones, and dances joyously. She then takes a payphone off its hook. During the pre-chorus, Lorde is inside the bathroom from the first scene with Antonoff playing piano in the background. Several shots of her dancing and moving her hair back and forth are shown, with one particular shot showing her placing her head down on what appears to be a car with flashing green lights. In the last scene, Lorde makes her way through an overpass at sunset, as a green light reflects on her face.
Lorde first promoted "Green Light" by posting