Extra Earth Life, as it currently stands, cannot simply mean life that exists beyond the confines of Earth's biosphere. There is an entire family of taxonomy used to provide labels for lifeforms in galactic society. EEL refers specifically to life that does not have a primary genetic origin point from Earth. This is a group that encompasses artificial intelligences that originate from a corporate world, the various races and species that evolved on other planets, and Benders. Generally speaking the only things that don't fall under this term are mankind and their purebred pets.
See also Artificial Intelligence
A.I.'s that are created from a brain-training model that was developed on a world other than Earth are technically considered EELs. This is a semantic point, obviously, considering that it applies to the majority of A.I.'s, but not quite all of them. No A.I. actually keeps track of this, however, and in most cases people are content to leave the extent of segregation leveled at A.I.'s to referring to them as "artificial".
This is, of course, the largest group to which the term EEL applies, and is the reason for the distinction between extra earth life and extraterrestrial life. This grouping includes all of the plants and various animals that evolved on the habitable worlds humans have settled, as well as the evolutions unique to terraformed archologies. Xenobiologists have enormous volumes dedicated to defining and tracking the development of these lifeforms, but that is obviously beyond the scope of this summary.
Intelligent lifeforms that fall into this category are actually shockingly rare. This turns out to be an extension of Humanity's genocidal tendencies, but is not in fact entirely their fault. For millions of years before mankind took to the stars a race even more genocidal than them waged an ongoing holy war across the width and breadth of the galactic plane, exterminating intelligent life wherever they could find it. These people, known officially as Aliens to mankind because they were the only alien life mankind ever got to meet, would frequently stumble across worlds inhabited by intelligent life, and then eradicate that life. On occasion they would find species that had made their own way into the galaxy, exterminate them, and then steal their technology.
This species is widely considered to be the primary reason behind Fermi's paradox. First contact with the zealot Aliens lost humanity a colony ship, and second contact served as an early warning to Earth. But unlike hundreds of other spacefaring species across millions of years, humanity managed to become aware of this holy war without making the Aliens aware of their homeworld. Humanity had a century to prepare for war before the Aliens, also colloquially called Creamies for their homogeneous skin color because humanity still has its issues, figured out that Earth was in a system they'd already purified; Sol.
After millions of years of victory the Creamies had become complacent. Their technology had stagnated for generations, and their leaders had grown overconfident, but they now faced a species nearly as genocidal as themselves. Humans had the scent that it was destroy or be destroyed, and elected to not go quietly into that good night. Technologically outmatched but to nowhere near the extent they should have been, humanity nevertheless overwhelmed their opponents with tactical understanding and motivation. In the end the Creamies were wiped clean from the galaxy, and Humanity took their place as the dominant form of life.
Later xenoarcheological exploration revealed the extent of the Alien's menace to the intelligent life of the Milky Way. Hundreds of thousands of intelligent cultures had been destroyed, hundreds of which had been spacefaring and might have made good allies to the fledgling interstellar humans. As it stands today, humans are the only known intelligent spacefaring species in the galaxy. They're currently watching several other species work their way toward civilization, but it may be hundreds more years before a first contact would be feasible.
The final campaign of the Alien war was not the first time Creamies had paid a visit to the Sol system. It's thought that part of the reason the inhabitants of Earth went undetected by them for so long was that a million years earlier they had paid a visit in order to purify Venus of its own spacefaring species. Xenoarcheological evidence of these people, understood only as the inhabitants of primordial Venus to the humans, is scarce at best. Venusians left their hot but habitable world while humanity was still swinging through the trees, and went exploring. They developed sophisticated engine technology that enabled them to reach beyond their home system, and just as they were beginning the worthwhile effort of colonizing neighboring star systems, the Aliens found them.
The war that resulted was fierce, but unfortunately not lengthy. The ancient Venusian's were hardy, but their assailants had the weight of numbers and technology stolen from a hundred other spacefaring peoples. Venus was rendered uninhabitable by their final onslaught to an extent that resists terraforming even a million years later. All the Venusians left behind were some heavily degraded ruins and the occasional lifeless vessel adrift in the stars. Their data storage technologies were either too volatile to survive a million years of the radio background of space or of a format that Humans have thus far been unable to recognize. In either case, virtually nothing has been learned of their culture.
Benders are, according to galactic policy, considered EELs. This is despite the fact that, when you come right down to it, they're just genetically engineered humans. Yes, their engineering is significant, and yes, it does result in the introduction of several new organs and abilities not common to humans. Still, their DNA is 99-point-repeating-9 percent identical to the rest of the human race, so there's really only one possible explanation for why this classification exists.
Racism. In case the fact that they're bought and sold as property didn't make that whole thing clear.
There are a number of intelligent lifeforms that exist in the galaxy that remain largely unknown to galactic society and even the larger scientific community. In most cases this is strictly because they want to remain hidden. The original intent was to keep themselves unknown to the Creamies, but their hesitation regarding Humans is understandable. After all, while it may appear that the Humans are less xenophobic than the religious zealotry of the Creamies, the comparatively infantile race of Humans single-handedly overthrew a millions-of-years-old galaxy-spanning oppressive regime in the space of a decade, so they're hardly pacifists. And to all outside appearances they do still enslave one particular subset of their own species.
Heritorns
See also Heritorns
A peace-loving, scientifically minded race of people who specialize in moving through and understanding subspace, known as Hawking space to humans. They are at least a million years older than the Human race, and may have actually had contact with the Venusians before they were wiped out. Heritorns were known to the Creamies by reputation, but they eluded the zealots for generations by essentially turning their home world of Herta into an enormous artificial habitat and quantum-locking the entire planet to a beam of light headed for another system so they could "dark jump" into unexplored space. The planet has no emissions, very little reflectivity, and they change systems every hundred years or so, meaning just about the only way to find the thing would be to randomly stumble across it.
Which is extremely unlikely, given that space is huge.
Terridinar, The Doctor (Terry)
The inter-dimensional being that calls itself Terridinar is about as close to God as anything in the known universe could claim to be. Those who know him call him Terry, and he is colloquially referred to as The Doctor given that he is, to all intents and purposes, a time lord. Terry hails from a parallel dimension layer to our own space-time that simply has no fourth dimension. Moving from our reality into his allows a being to exist in every traversable point they will cross while there simultaneously. This is the mechanism that allows benders to, you know, bend.
Terry is the only intelligent being to have evolved in his universe that he is aware of, and considering he exists in every point of his universe, it seems pretty likely he'd know. Benders make contact with Terry every time they bend, and they tend to think of him as almost a benevolent guide. He travels with them, keeping them company as the unique function of the Terkius array allows benders to perceive their passage of space without the assistance of time. And then he bids them farewell as they return to our space-time, completing a journey that is imperceptible to humans limited sensory capabilities.
No bender has ever mentioned the existence of Terry to a non-bender, and they typically communicate about him telepathically to avoid eavesdropping. Terry does occasionally poke his head through into our universe, able to traverse space outside of time and seemingly aware of the entire course of history at once. He doesn't do it often, and then only to do favors for benders he particularly likes. Interestingly, he has been known to just stop by the Eclipse to check in with the Bender for no reason whatsoever.
At one point the word 'terra' was used to mean Earth, but it's original meaning of 'land' is what has been carried forward in scientific taxonomies. Once humanity started colonizing other worlds extraterrestrial could no longer simply mean "not from Earth" given the sheer number of humans who considered themselves "terrans" there were who didn't come from Earth. As a way to appease the galactic community writ-large, the term extra earth life was introduced, and extraterrestrial was repurposed to mean life that originated in space, rather than on a planet.
For the most part this consists of the generations of people and AIs who are born, live, and die on starships or space stations of some sort. Large stations, such as the lunar orbital habitats around Earth, have introduced some gray into the terminology, because an extremely massive artificial habitat does in fact necessitate the presence of dirt land masses that might be considered... well, terra-firma.
Extraterrestrial life would also refer to life that simply exists in space and did not come from a planet. Humanity hasn't met any life like that, but the lingering Star Trek fandom continues to hope.