CSI (plural CSIs)
- Initialism of Crime Scene Investigation (a term of forensic science)
- (informal, US) Initialism of Crime Scene Investigator.
- Initialism of Customer Satisfaction Index.
- Initialism of Committee for Skeptical Inquiry (formerly CSICOP)
- (India) Initialism of Computer Society of India.
- -ics, CIS, ICS, ICs, I²Cs, SCI, SIC, Sci., cis, cis-, sci, sci., sic