Cyber is a prefix meaning “related to computers, the internet, or digital technology.” It comes from cybernetics, a word coined in the 1940s for the science of how systems communicate and control themselves, whether mechanical, biological, or electronic.

You encounter cyber everywhere in modern life. Cybersecurity protects computer systems from hackers and thieves. A cyber attack is when someone tries to break into computer networks to steal information or cause damage. Cyberbullying happens when people use phones, social media, or online games to harm others. When stores offer Cyber Monday sales, they're focusing on online shopping rather than in-person retail.

In the 1980s and 1990s, people used cyber to make everything sound high-tech and exciting: cyberspace for the digital world, cybercafé for coffee shops with internet access.

Today, since nearly everything involves computers, adding cyber to a word specifically emphasizes the digital or internet-connected aspect. A cyber threat isn't just any danger; it's one that comes through computer networks. Understanding what cyber means helps you make sense of countless modern terms, from cyberwarfare between nations to cyber literacy programs at school.