interjection
Archaic interjection expressing 'in that way' or 'so'. Not used in modern conversation; appears in classical texts.
古語では「しか」は「そのように」という意味の感動詞として使われた。
In classical Japanese, しか was used as an interjection meaning 'like that' or 'as such'.
interjection
Casual interjection of agreement or acknowledgment, similar to 'yeah' or 'uh-huh'. Used in informal speech.
「明日、映画に行かない?」「しか。」
"Wanna go to a movie tomorrow?" "Yeah."
友達の話に「しか」と相槌を打つ。
I nod along to my friend's story with an 'uh-huh'.
Derived from classical Japanese 然 (shika), meaning 'in that way'. The casual interjection sense developed from the archaic meaning, but the exact path is uncertain.