Antivirus software is a type of security software that is designed to detect, prevent, and remove malicious software (malware) from a computer or network. Antivirus software works by scanning files and programs for known patterns of malicious code, and by monitoring system activity for signs of a malware infection. Here are some key features of antivirus software:

1. Scanning and detection: Antivirus software scans files, folders, and other areas of a computer or network to detect malware. This can include scanning email attachments, downloads, and external devices such as USB drives.

2. Real-time protection: Many antivirus software programs offer real-time protection, which means they monitor system activity in real-time to detect and block malware before it can cause harm.

3. Quarantine and removal: When antivirus software detects malware, it typically quarantines the infected file to prevent it from spreading and causing damage. The software may also attempt to remove the malware from the system entirely.

4. Updates: Antivirus software must be regularly updated to stay current with the latest threats. Updates typically include new virus definitions, which are patterns of code used to identify known malware.

5. Firewall protection: Many antivirus software programs also include firewall protection, which helps to prevent unauthorized access to a computer or network.

6. Performance optimization: Antivirus software can also optimize system performance by scanning for and removing unnecessary files, temporary files, and other types of system clutter.

Overall, antivirus software is an essential component of a comprehensive security strategy. By providing real-time protection, scanning and detection, quarantine and removal, updates, firewall protection, and performance optimization, antivirus software can help protect against a wide range of malware threats and keep computer systems running smoothly.