It occurred to me today that I’d never satisfactorily answered this question to anybody, even though I’ve been asked many times. Unfortunately, that’s because it’s a two-part answer and requires a logical leap.
The first part is Ether.
To understand this you need to go back a little over a hundred years. Physicists of the 19th century were struggling to understand how light got from the sun to the Earth, and why it behaved the way it did; the belief that light was a particle explained many of its behaviors (like reflection) but not others (like refraction). To explain this, scientists proposed a medium through which light traveled, the luminiferous aether. Invisible and omnipresent, it allowed light to travel through what was otherwise assumed to be a vacuum, and faster-than-light propagation of waves caused by the light explained the odd non-particle behaviors.
Naturally, Einstein showed up in the early 20th century and screwed the whole thing up with Special Relativity, but that’s neither here nor there.
In the mid-70s, engineers at Xerox developed a computer-networking protocol that was superior both in speed and in usability to the then-prevalent but highly-proprietary Token Ring and Token Bus systems. Unlike the Token systems, each system on Xerox’s network could see each other system, regardless of whether the systems were linked serially (that is, each computer hooked to the next in sequence, like elephants in a row, trunk-to-tail), hubwise (a central core into which each computer hooked, like an octopus), or otherwise. The new networking protocol, in effect, allowed the computers to pretend that there was an invisible, pervasive medium surrounding them, through which they could propagate messages to other systems, much like the sun propagated light to the planets.
In a fit of pique, the Xerox engineers (who were now working with Digital and Intel to finalize the standard) named their protocol after the luminiferous aether, and thus Ethernet – the networking protocol by which the vast majority of local internet nodes communicate – was born.
The second part is jammer, and although it’s a lot simpler to explain, I’ll wager that fewer of the people who read this will have run across the origin of this part before.
To understand this part, we need to go back to the late Age of Sail, just before the advent of steamships. There were two major classes of shipping vessels then: the clippers, which held a smaller cargo and were less maneuverable but were much faster, and the windjammers, which were larger and slower, but carried more cargo, were more maneuverable, and – speed aside – were generally more capable ships than the clippers. (Both of these, sadly, were displaced by steamships, which – unlike clippers and windjammers, which were both sailing ships – were not reliant on the wind to get from point A to point B.)
Combining the two gives us Etherjammer: a large, flexible, maneuverable ship that plies the open Ethernet; not the fastest ship in the fleet, but adaptable and able to deal with a wide array of tasks.
(Yes, it’s a metaphor.)