signature phrase; catchphrase; trademark line
A distinctive line or phrase repeatedly used by a character, performer, or public figure, often delivered at a climactic moment. Common in anime, manga, drama, and pro wrestling.
彼の決め台詞は「真実はいつもひとつ！」だ。
His signature phrase is 'There is always only one truth!'
その芸人は決め台詞で会場を沸かせた。
The comedian got the audience going with his trademark line.
決め台詞 is a signature catchphrase a character repeats, while 名台詞 is any single line that became famous, whether repeated or not.
Standard kanji spelling.
Mixed kanji-katakana spelling, common in manga and entertainment contexts.
Mixed katakana-kanji spelling, also seen in pop culture.
Rare kanji form using 科白 for せりふ.
Full katakana spelling, often used for emphasis or stylistic effect.
Compound of 決め (kime, 'deciding' or 'climactic', from 決める) and 台詞 (serifu, 'line' or 'speech'). The term likely originated in theater and was later adopted in film, television, and manga to describe a character's iconic line.