So Electronic MAIL, literally meant the Electronic version of MAIL. What was MAIL in 1978? MAIL meant inter-office communications. Such a communication was called a "letter" or "memorandum" or "inter- intra-office mail". A typical MAIL had the title of MEMORANDUM, with "To:", "From:", "Date:", "Subject:", "Cc:", "Bcc:", "Attachment", elements. This was the meaning of MAIL. "Electronic MAIL" system - one that would convert the paper transmittal of MEMOS with an electronic equivalent for UMDNJ.
See this info-graphics. Click on the info-graphics to enlarge.
