A massive amount of email that is sent to a specific person or system, consuming the recipient’s disk space on the server or creating an overload situation for the server, which causes it to slow down considerably or stop functioning altogether. In the past, mail bombs have been used to punish Internet users who are netiquette violators (such as those who spam others on the Internet). TechTarget. Mail Bomb. [Online, October 28, 2003.] TechTarget Website. http://searchsecurity.techtarget.com/gDefinition/0,294236,sid14_gci212514,00.html.
To send a mail bomb (in either sense)