Origins
The word 'email' is a compound coined in the age of computer networking, but its two constituent parts reach back into the deep history of language. 'Electronic' traces to ancient Greek; 'mail' traces to the Frankish warriors who helped build medieval Europe. Together they form one of the most widely used words coined in the 20th century.
The first element, 'electronic', derives from the noun 'electron', which was coined in 1894 by the Irish physicist George Johnstone Stoney to name the unit of electrical charge. Stoney based his coinage on the Greek word ēlektron, which meant 'amber'. The connection was not arbitrary: the ancient Greeks had observed that amber (a fossilised tree resin), when rubbed against cloth, attracted small particles — the first recorded observation of static electricity. The Greek word ēlektron may itself derive from a word for the sun, reflecting amber's golden colour, though this etymology is disputed.
From 'electron' came 'electronics' (1910s) and 'electronic' as an adjective (1902). The prefix 'e-' as a shorthand for 'electronic' became productive in the late 20th century: e-commerce, e-book, e-government, e-learning all follow the same pattern as e-mail.
Proto-Indo-European Roots
The second element, 'mail', has a different and equally deep history. It entered English from Old French male, meaning 'a bag', 'a wallet', or 'a pack'. The Old French word derived from Frankish or Old High German *malha, meaning a leather bag or wallet — the sort of bag that a messenger or traveller would carry on horseback. This Germanic root is also the ancestor of the modern French 'malle' (a trunk or large luggage), and may be related to Middle Dutch male.
In English, 'mail' originally meant a bag for carrying letters and dispatches — the mail bag. From the container it shifted to the contents: the mail was the collection of letters the bag contained. Then it shifted further: to deliver the mail, to send something by mail, and eventually 'mail' as a general term for any postal communication. This metonymic shift (container to contents to act) is very common in the history of words for communication and transport.
The phrase 'electronic mail' appears in computer science and government documents from approximately 1979, following the development of ARPAnet email systems in the early 1970s. Ray Tomlinson is credited with sending the first network email in 1971 and with choosing the '@' symbol to separate the user name from the host machine — a decision of extraordinary consequence for the shape of modern communication.
Word Formation
The hyphenated 'e-mail' appears in print from around 1982 and was the standard form through the 1980s and 1990s. The unhyphenated 'email' gradually became dominant in the 2000s as the word lost its sense of being a novel compound and became a fully integrated common noun. Style guides spent years debating hyphen versus no-hyphen before most settled on the unhyphenated form.
As a verb, 'to email someone' follows the long English pattern of converting nouns for communication methods into verbs: to telephone, to fax, to text, to tweet — and now to email. The verbal use was established in the late 1980s and is now entirely standard.
The cultural weight of 'email' is enormous. It redefined the pace of written communication, compressed the response time from days to seconds, and created new genres of writing — the office memo became the email thread, the business letter became the cold outreach, the personal letter became the message that competes with dozens of others for attention. Linguistically, it also spawned a vocabulary: inbox, outbox, cc, bcc, spam, thread, attachment, bounce — many of these terms borrowed or extended from older communication contexts, some coined anew. The amber of ancient Greece, and the leather bag of a Frankish messenger, live on in every electronic message ever sent.