Start with the words about you. Your bias is your favorite member of a group — the one whose fancams you loop. A bias wrecker is the member who keeps threatening to take that spot, and your ult (ultimate) is the bias above all biases, across every group you follow. K-pop assumes you'll have all three, and comment sections make a sport of the rivalry.
Next, the release cycle. A comeback is any new release from an active group — no hiatus required — and the whole package around it (the concept, styling, photos and sound) is that comeback's era. The title track is the song being promoted with a music video and broadcast stages; everything else on the record is a B-side, and fandoms defend their favorite B-sides fiercely. For the full machinery, our comeback-cycle guide walks teaser-to-encore in order.
Then the scoreboard words. An all-kill means a song hits number one on the major Korean charts at the same time, and the rarer perfect all-kill requires holding them simultaneously, realtime and daily alike. Chodong is first-week album sales — the number fandoms treat as a loyalty census, covered in its own guide here — and a music-show win is the trophy a comeback chases on weekly broadcast charts.
Finally, the live culture. A lightstick is a group's official light — each fandom has its own design, and an arena of them synced to the music is K-pop's signature image. A fanchant is the crowd's scripted part: names and lines shouted in the gaps of a song, learned in advance by the whole fandom. And when the promoted run ends, the encore stage closes an era — until the next comeback starts the dictionary over.