HCI

• Happy Computers, an American computer hardware manufacturer
• Home Computer Initiative, a United Kingdom government programme to increase computers usage
• Host controller interface (disambiguation), various computer interfaces
• Human–computer interaction, the study of how people interact with computers
• Human-computer interaction (security), the study of how people interact with computers concerning information security
• Hyper-converged infrastructure, an IT infrastructure framework for integrating storage, networking and virtualization computing in a data center.

• Harbord Collegiate Institute, a school in Toronto, Canada
• Humberside Collegiate Institute, a school in Toronto, Canada
• Hwa Chong Institution, a school in Singapore

• Highly charged ion
• Hot carriers injection, in solid-state electronic devices
• Hydrocarbon indicator, in reflection seismology

• Handgun Control, Inc., the former name of the Brady Campaign to Prevent Gun Violence
• Harrisburg City Islanders, a soccer club from the United States
• HCI Books (Health Communications Inc), an American publishing house, see What the Bleep Do We Know!?
• Human Concern International, a Canadian relief and development organization
• Huntsman Cancer Institute, an American cancer research facility and hospital

• Heavy-Chemical Industry Drive, a former economic development plan of South Korea

• HCL (disambiguation)
• HCIL (disambiguation)
• HCl (H-C-lowercase L), chemical formula of Hydrogen chloride

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