Loona (stylized as LOOΠΔ, Korean: 이달의 소녀; Hanja: 本月少女; RR: Idarui Sonyeo; MR: Idarŭi sonyŏ; lit. "Girl of the Month") is a South Korean girl group formed by Blockberry Creative. The group was introduced to the public through a pre-debut project which began in October 2016, where each of the twelve members were revealed in a periodic fashion by releasing a promotional single over the following eighteen months. They debuted as a full ensemble with the extended play, [+ +] (2018), supported by the lead single "Favorite" and the title track "Hi High".