You are correct in stating that there may be (and probably is) a better name for "dark energy", but I doubt there will be any agreement about what that might be anytime soon. The problem is that the "shape" of the Universe depends on the ratio of its mass/energy to its overall size. If the mass/energy is significantly greater than the "critical" value, the Universe would eventually stop expanding, then collapse to a point of zero size (a sort of reverse Big Bang). This was actually a highly favored theory in the middle of the twentieth century, but as our ability to measure the motions of stars inside galaxies and of galaxies in clusters of galaxies improved, it became obvious that the visible matter in the Universe was far less than the critical value. This led to the idea that "normal" matter was only a few percent of the critical value, but that "dark matter" made up enough extra mass to make the overall mass of the Universe very close to the critical value (in other words, dark matter was far more abundant than normal matter, by a factor of as much as 20 or 30 times). The development of the Inflationary Theory, in which the Universe expands from practically zero size to tens of billions of light years' size in a time comparable to the Planck time, implied that the Universe should now be so large in comparison to any part that we can see that, just as the surface of the Earth looks essentially flat to anyone on the ground (particularly in Kansas), the Earth is actually a roughly spherical globe. In a similar way, though the overall Universe was presumably some gigantic roughly spherical object (visualizing it in three dimensions in the same way that a drawing of a sphere on a piece of paper visualizes it in two dimensions -- that is, it is not really a sphere, but it is spherical in that it is presumably about the same size in all directions), any part small enough for us to see should look "flat". But that would require , as stated above, that the mass-density of the Universe be close to the critical value.

This idea was considered so essentially unquestionable in the late 80's and early 90's that anyone who disagreed with the idea that dark matter was sufficiently abundant to make the mass density more or less equal to the critical value was laughed out of the cosmological playroom, metaphorically speaking. However, this led to a serious problem with various estimates of the age of the Universe (there is a rough discussion of this, as I saw it in the mid and late 90's, on my website at http://cseligman.com/text/galaxies/universe.htm (The Expansion of the Universe), which shows that if the Universe had a mass density close to the critical value, it would have to be less than half as old as the oldest stars, which is ridiculous), and about the turn of the century there was a crisis that led to the abandonment of the idea that dark matter made up enough mass (even though it is still considered to be far more abundant than normal matter) to be close to the critical value (and in fact can't be much more than a quarter of that value).

But if the Universe appears flat, in the sense that the part we can see is too small to have any obvious non-flat shape, regardless of its "actual" shape, then how do we explain this? The answer was to replace the "missing" dark matter with something else -- something that had nothing to do with matter at all -- which was dubbed dark energy. It IS dark, in the sense that unknown things ("darkest Africa", the "dark side of the Moon", etc) have always been referred to as dark, meaning we know nothing about them. But whether it is energy is another matter. It is just called that for lack of a better name. It could well be that dark energy does not exist at all, and is simply a way of describing Einstein's prediction that sufficiently large amounts of empty space have a tendency to expand; and if dark "energy" DOES exist, it probably isn't a form of energy at all, but something completely different. But the term was invented to ensure that (normal mass + dark matter + dark energy) still equals 100% of the critical mass density of the Universe, even though "dark matter" is far too rare to do the job. And once invented to solve a then insoluble problem, the term isn't likely to go away unless and until it is proven that there IS something other than Einstein's prediction going on, and just what that is. I wouldn't hold my breath waiting for the answer to that question to be determined, as it took decades to get rid of the idea of dark matter taking care of the job, and we still have no real idea what dark matter is (see Dark Matter in Galaxies, at http://cseligman.com/text/galaxies/dark.htm for a discussion of various ideas that have been suggested and abandoned, and how the current hope arose that it is something that "any day now" we can hope to prove what it is (thereby giving someone a Nobel Prize for doing just that), since the equally great possibility that it will turn out to be something very difficult to prove, but so boring that no one will really care, is not conducive to publishing papers. Odds are, dark energy will follow the same route, but over a longer time period.

Dark energy is somehow a feature of space-time itself, so it expands in kind as the universe expands. That means that the "energy" part of dark energy is a misnomer.

Problem is to do with the interpretation of the cosmological constant Λ in the standard ΛCDM cosmology. So you can give any name you want as long as it reproduces required non vanishing value of Λ in Einstein field equations,

Rμν -1/2 R gμν + Λgμν=8πG/c4 Tμν.

When Λ=0, in the weak field limit you will recover Poisson's equation for Newtonian gravitational potential Φ , but if Λ≠0 you will not recover Newton's Physics exactly, an extra linear term in Φ will hang around in your Newtonian limit, which is proportional to Λ/c2.

Adding to Biswajoy's excellent reply, the justification of using "energy" comes from the right-hand side of Einstein's equation which includes the so-called energy-momentum or stress-energy tensor Tμν. The Λgμν term can be absorbed in the right-hand side term and described as an energy density tensor term.

The question is well posed and well-answered in a formal sense, but also misses the fact that a memorable, short-hand term is needed that may or may not encompass all possible physical explanations. Consider "dark matter". The word "dark" originated from the lack of being able to "see" what was involved, except by gravitational effects. The adjective applied equally to our lack of physical enlightenment. The search for "dark matter" led to searches, many of them expensive, for small black holes, neutrinos and massive, exotic particles, in addition to suggested (and refuted) reformulations of gravitational physics. Some of these searches were not for "matter", but the term nevertheless remained a useful shorthand reference to the subject. The same applies to "dark energy". The observed distant redshifts may (probably?) not be caused by "energy", but the term provides a useful and popular shorthand way to capture the subject matter and importantly, popular interest in further research efforts.

Gentlemen,

The main problems of uasmology are solved relatively simply. The relativistic description of a homogeneous space surprisingly connects the density of the universe and the Hubble law. At this time, the distance from the observer changes with acceleration compared with the law. Hubble. At the same time, the dark energy, the concentration of which is dark meteoria, will be explained

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Einstein's ideas are good, they need to be developed.

Preprint Dark energy as zero energy of gravity field