- Affectionate Nickname: Jinsoul calls Olivia Hye "Boss Baby" because she's super professional on-stage, but the most adorable kid off-stage.
- Blooper: The MV for "LOONATIC" features several unused or alternate ODD EYE CIRCLE cuts from their own other music videos. One is a wide-view cut from "Love Cherry Motion" that was originally zoomed in enough to hide JinSoul hitting her head on the ceiling of the set offscreen.
- Childhood Friends:
- Heejin and Hyunjin, who still go to school together and are inseparable.
- Chuu and Kim Lip both attended and finished high school together. They had no idea they would debut in the same group either.
- Dyeing for Your Art: Kim Lip and Jinsoul dyed their hair blonde, and their blondness coupled with their "girl crush" concept signaled a new era for the pre-debut project.
- While Go Won's first promotional photo showed her with black hair, the following one showed that she also dyed her hair blonde. In her MV, she initially appears with black hair, then becomes blonde after eating a piece of pineapple. LOONA TV shows that Park Chae Won actually dyed her hair thrice for Go Won: she dyed her black hair blonde first for photoshoots before shooting "One&Only", then recorded her blonde scenes before dyeing her hair back to black for the rest of the video. Once it was over, she dyed her hair the blonde she kept for a long time after.Go Won: [LOONA TV #400] Somebody told me that I bleached my hair and dyed it back to black and bleached it again! (Is your scalp okay?) Yeah, but I'm worrying about my future. Cheer up, my scalp!
- And later, Chuu dyed her hair red for the debut of the full group. At the same time, Kim Lip began letting her hair fade back before going full brunette, and Chuu did the same as [xx] approached. Choerry and ViVi would go purple-headed and red-headed for the comeback, however.
- While Go Won's first promotional photo showed her with black hair, the following one showed that she also dyed her hair blonde. In her MV, she initially appears with black hair, then becomes blonde after eating a piece of pineapple. LOONA TV shows that Park Chae Won actually dyed her hair thrice for Go Won: she dyed her black hair blonde first for photoshoots before shooting "One&Only", then recorded her blonde scenes before dyeing her hair back to black for the rest of the video. Once it was over, she dyed her hair the blonde she kept for a long time after.
- Fan Community Nicknames: Loonatics, though it's unofficial. Orbit is the official fanbase name as of July 9, 2018.
- Fan Nickname: With 12 girls, several of whom happen to have a stage name, the fans tend to get very creative.
- Flip-Flop of God:
- Whether or not the "Heart Attack" music video is meant to be interpreted in a romantic sense or not is kind of ambiguous. The music video itself has imagery that's very evocative of romantic love in general, such as arrows through the heart and the strawberry-sharing (which are symbolic of romantic feelings being returned), but the description for the music video describes it as interpreting love "not in a serious way, but in Chuu's own adorable emoticon-like ways". Chuu herself explained commented on variety show Fact In Star that, "Heart Attack" was about "me approaching someone I love, like this [demonstrating key choreo], while confessing my feelings."
- There was some debate about Olivia Hye's identifying color for a while; although she said in a fansign that it's silver, she is always denoted by #00000 black in any material her face is not explicitly shown in. Further clarification reveals that both are technically correct: her color is "shades of gray" and spans every shade from white to black.
- Meta Casting: Wong Kahei's origins from Hong Kong being written into Vivi's character in the LOONAVERSE was revealed in a Cinema Theory clip in a rather chilling way. The clip in question begins as a video-diary-esque letter to her parents back in Hong Kong, with Vivi speaking in her native Cantonese and describing the daily lives of the members of 1/3 in a way that seems to perfectly match their real-life counterparts... until she and HaSeul visit an aquarium, and Vivi's camera shorts out once she finds JinSoul in the crowd with her eyepatch from "Sweet Crazy Love." Given that, the clip also seems to imply that the real lives of LOONA 1/3 are, to a degree, shared with their LOONAVERSE counterparts.
- Name's the Same:
- Loona (not caps-locked) is also the name of a known Dutch pop singer.
- What Could Have Been:
- LOONA TV shows that the bonus clip of HeeJin doing the rap portion of "Singing In the Rain" was originally meant for Kim Lip, explaining the deep red lighting. Since it was bonus material, the rap actually came as a surprise to Kim Lip in the middle of shooting JinSoul's MV, and since she wasn't too confident about her rapping she called in HaSeul as backup. LOONA 1/3 came along with her, and HeeJin was so eager to try out a girl-crush style concept that BBC gave her a shot as well. BBC recorded all three of them and ended up choosing HeeJin's clip.
- The stage name "Adam", and variations thereof, were suggested for every member of yyxy debuting after Yves. While it seemed to be a deliberate gag for Go Won, all the members turned the name down anyway.
- As meticulous as DigiPedi is for the artistic choices in music videos, some cuts and set decisions had to be changed or dropped. The dance portions of "One&Only" after Go Won turns blonde, for example, originally had dry ice on the floor for a mist effect, but Go Won and the dancers found it too slippery to keep, so they had to go without it. Both of Olivia's fish flops (the reverse somersaults) also never made it to the music video for "Egoist".
Trivia / LOONA