Final answer:
Unsolicited junk email is commonly referred to as spam. It's typically sent in bulk for advertising or malicious purposes and is considered a form of Internet nuisance.
Step-by-step explanation:
The term for unsolicited junk email is spam. Spam refers to irrelevant or inappropriate messages sent over the Internet to a large number of recipients, often for advertising, phishing, spreading malware, or just as a nuisance. Although 'junk mail' can also be used to refer to unwanted email in a more general sense, spam is the correct specific term when it comes to unsolicited bulk email messages.