C1, C01, C.I or C-1 may refer to:
==Arts and media== C1, a note-octave in music C1 Television, a Mongolian television channel Cinema One, Philippine pay TV channel Schecter C-1 Hellraiser FR, a guitar model A Yamaha grand piano model "C1", a slang expression in the video game Counter-Strike, used to express agreement
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).