Final answer:
A spam filter is software designed to prevent unwanted email, known as spam, from reaching a user's inbox. It uses various criteria to identify and segregate spam, helping to protect against clutter and potential threats.
Step-by-step explanation:
Computer software that is designed to prevent spam messages from entering into a user's e-mail inbox is called a spam filter. Spam refers to unwanted email messages, often of a commercial nature, sent indiscriminately to multiple mailing lists, individuals, or newsgroups. Spam filters can be integrated into email software, and they typically work by analyzing the content of emails against set criteria and known spam indicators, such as specific phrases, sender reputation, unusual patterns, and more. When an email is identified as spam, it is usually directed to a separate folder where the user can review and delete it, if necessary. This helps keep the inbox free from clutter and potentially harmful content that might accompany spam, such as malware or phishing attempts.