Other forms: catchphrases
A catchphrase is a line a character or a performer says so often that it becomes famous on its own. A comedian's catchphrase, the show's catchphrase, everybody knew the catchphrase.
It belongs to television, comedy and advertising, and the test is repetition: a memorable line said once is a quotation, and a line said every week is a catchphrase. Politicians have them too, though there they are usually called slogans, which are written on purpose rather than caught. Note that a catchphrase can outlive the programme it came from by decades, which is exactly what makes it worth having.
1nouncatchphraseA line repeated so often by a character or performer that it becomes well known.
“The catchphrase outlasted the series by twenty years.”
catchphrase is a repeated phrase.
From catch + phrase, from the notion that the phrase will catch in the mind of the user.
Etymology from Wiktionary, CC BY-SA