NCT (Hangul: 엔시티) is a South Korean boy group formed by S.M. Entertainment. Their name stands for the Hallyu localization project Neo Culture Technology, a term coined by S.M. Entertainment founder Lee Soo-man to describe the group's concept of having an unlimited number of members divided into multiple sub-units based in various cities worldwide. The group's first unit, NCT U, made their debut in April 2016 with the digital singles "The 7th Sense" and "Without You". The second unit, NCT 127, based in Seoul, made their debut in July 2016 with the mini album NCT #127.The third unit, NCT Dream, made their debut in August 2016 with digital single "Chewing Gum". It was reported that subsequent units were to debut based in China, Japan, Thailand, Vietnam and Indonesia. As of February 2018, the group consists of 18 members: Taeil, Johnny, Taeyong, Yuta, Kun, Doyoung, Ten, Jaehyun, Winwin, Jungwoo, Lucas, Mark, Renjun, Jeno, Haechan, Jaemin, Chenle, and Jisung.

Pre-debut All the members of NCT except for Renjun and Chenle were formerly part of SM Rookies, a pre-debut group of S.M. Entertainment trainees. In January 2016, S.M. Entertainment founder Lee Soo-man gave a presentation at the SM Coex Artium titled "SMTOWN: New Culture Technology 2016", speaking about the agency's plans for a new boy group in line with their "culture contents" strategy that would be debuting different teams based in different countries around the world.

2016: Debuts of NCT U, NCT 127, and NCT Dream

On April 4, 2016, S.M. Entertainment announced NCT's first unit, NCT U, consisting of six members: Taeil, Taeyong, Doyoung, Ten, Jaehyun and Mark. NCT U released double digital singles "The 7th Sense" on April 9 and "Without You" on April 10 in two versions (a Korean version sung by Taeil, Doyoung, and Jaehyun, and a Chinese version with the addition of SM Rookies' Kun). On April 9, 2016, NCT U made their first broadcast appearance with NCT On Air on Naver V-app, hosted by Super Junior's Kim Hee-chul. The same day, they had their first live performance in China at the 16th Music Feng Yun Bang Awards along with two other Chinese members, Kun and WinWin. The group made their debut in Korea on music program KBS's Music Bank on April 15 and have subsequently appeared in three seasons of their reality series NCT Life, featuring other SM Rookies.

On July 1, S.M. Entertainment announced NCT's second unit, NCT 127. NCT 127 is based in Seoul, with the number "127" representing the longitude coordinate of Seoul. The unit consists of seven members: Taeil, Taeyong, Yuta, Jaehyun, WinWin, Mark and Haechan (formerly known as Donghyuck). On July 7, they had their official debut stage on the music program M Countdown, performing their title track "Fire Truck" and "Once Again" from their album. Their debut EP NCT #127 was released digitally on July 10 and physically on July 11. On July 29, the unit released the single "Taste the Feeling" for the project SM Station in collaboration with Coca-Cola. On August 18, S.M. Entertainment announced that NCT's third unit would be called NCT Dream. The unit consists of seven members: Mark, Renjun, Jeno, Haechan, Jaemin, Chenle, and Jisung. Their first single "Chewing Gum" was released on August 24 and the unit had their debut stage on M Countdown on August 25.

On December 6, 5 members of NCT 127 (Yuta, Taeyong, Jaehyun, Mark and Winwin) released a special dance music video titled "Good Thing" in collaboration with W Korea.[29] The single was eventually released on NCT 127's second mini album, Limitless. On December 20, the music video for "Switch" was released. The single was previously released as a bonus track on NCT 127's mini album NCT #127, and features SR15B.[

2017: Comebacks of NCT 127 and NCT Dream

On December 27, NCT 127 announced that they would be making a comeback with the addition of two members, new member Johnny and NCT U's Doyoung. On January 5, 2017, the music videos of "Limitless" was released and the unit had their comeback stage on M Countdown. Their second mini album Limitless was released digitally on January 6, 2017 and physically on January 9, 2017. Limitless debuted at the number one spot on Billboard's World Albums Chart. "Limitless" was named by Dazed Digital as one of the top 20 best K-Pop songs of 2017. On February 1, 2017, NCT Dream announced that they would be releasing their first single album The First on February 9. SM Entertainment announced that Jaemin would not be participating in this comeback due to health problems. The unit had their comeback stage on M Countdown, performing the title track "My First and Last" and the B-side track "Dunk Shot". On February 14, NCT Dream was revealed to have won 1st place on the 100th episode of SBS MTV's The Show. This marked the first music show win for a NCT unit. NCT Dream was also unveiled as the official ambassador for the 2017 FIFA U-20 World Cup Korea. They released the official theme song, "Trigger the Fever" on March 15.

On March 8, 2017, NCT 127 members Johnny and Jaehyun was announced as the new DJs for SBS Power FM new program, NCT's Night Night.The radio program started to air on March 20. On June 14, 2017, NCT 127 released their third mini album, Cherry Bomb. They had their first comeback stage on M Countdown, performing their title track "Cherry Bomb" and "0 Mile" from their album."Cherry Bomb" was chosen by Billboard and Idolator as one of the best K-pop Songs of 2017. On August 17, 2017, NCT Dream released their 1st mini album We Young. The unit had their first comeback stage on M Countdown, performing the title track of the same name. In December 2017, NCT Dream released their first Christmas song, "Joy". 2018–present: New members, large-scale projects and NCT 2018 Empathy In January 2018, NCT U/127 (Taeil, Doyoung, and Jaehyun) released the single "Timeless" as part of the SM Station project.[50] In mid-January 2018, NCT unveiled NCT 2018, a project involving all 18 members of NCT.

On January 30, 2018, SM Entertainment released a video titled "NCT 2018 Yearbook #1," which features existing members and introduced new members Kun, Lucas and Jungwoo. In February, NCT released a series of online documentary videos titled NCTmentary as part of NCT 2018. Later, on February 13, SM Entertainment announced the first part of the NCT 2018 series with the comeback of the rotational unit NCT U, comprising of existing unit members Taeyong, Doyoung, Jaehyun, Winwin and Mark, and new members Lucas and Jungwoo. On March 14, 2018, NCT released its first full-length album NCT 2018 Empathy. As part of NCT 2018, the group has promoted and released a series of music videos for principle tracks from Empathy, including: "Boss" (performed by NCT U), "Baby Don't Stop" (performed by Taeyong and Ten as part of NCT U), "Go" (performed by NCT Dream), "Touch" (performed by NCT 127) and "Yestoday" (performed by Taeyong, Mark, Doyoung and Lucas of NCT U).[55] The final track "Black on Black" includes all 18 members of NCT. On May 2, 2018, NCT has become the top emerging musical act in the U.S. and marked the first time that a K-Pop act has led the list, reported by Billboard.- Wikipedia