Glossary

Fringe-energy claims lean heavily on scientific-sounding vocabulary. Here are plain definitions so the words don't do the persuading for the argument.

Energy and thermodynamics

Conservation of energy (first law of thermodynamics): The principle that energy cannot be created or destroyed, only transformed. It is why a machine cannot output more usable energy than it takes in.
Second law of thermodynamics: In any real process, some energy is dispersed as low-grade heat and overall disorder (entropy) tends to increase. It is why no machine is perfectly efficient and none can run forever off its own output.
Entropy: A measure of disorder or of energy that is no longer available to do useful work. It tends to increase in isolated systems.
Efficiency: The fraction of energy input that a machine converts into useful output. Real machines are always below 100%.

The fringe claims

Free energy (in the fringe sense): The claim of a device that supplies usable power with no fuel and no external energy source. As used here it is not accepted by mainstream science. (Note: physicists also use “free energy” for a legitimate, unrelated technical quantity.)
Over-unity: A claimed efficiency greater than 100% — more energy out than in. This is another name for a perpetual-motion machine and is considered impossible.
Perpetual motion: A hypothetical machine that runs indefinitely and/or does work without an energy source. Ruled out by the laws of thermodynamics; patent offices generally refuse such applications without a working model.
Searl Effect Generator (SEG): The magnetic device claimed by John Searl to produce continuous “free energy.” A claim, not an established effect.
Levity disc / Inverse-G-Vehicle (IGV): The disc-shaped craft Searl claimed could fly using the Searl Effect. Unverified; no accepted physics supports magnet-based anti-gravity.
Zero-point energy: A real feature of quantum physics: the lowest possible energy of a system. There is no demonstrated way to extract usable net power from it, despite frequent appeals to it in fringe-energy claims.
Anti-gravity: A hypothetical technology that cancels or reverses gravity. No working device exists; it is not part of mainstream physics.

Thinking tools

Pseudoscience: Claims or practices presented as scientific but lacking the evidence, testability, or methods that science requires.
Burden of proof: The principle that the person making a claim must provide the evidence for it — not that others must disprove it.
Falsifiability: Whether a claim could, in principle, be shown false by evidence. Claims that can never be tested are not scientific.
Extraordinary claims: The idea, associated with Carl Sagan, that the more a claim departs from established knowledge, the stronger the evidence it needs.

How these words get misused

The danger with technical vocabulary is that it can persuade by sound rather than sense. In fringe-energy claims, real terms — “quantum,” “zero-point,” “resonance,” “the vacuum” — are frequently used far outside their actual meaning, as a kind of scientific decoration. The words signal authority to a general audience while the underlying claim quietly assumes something impossible, such as energy created from nothing. A useful habit is to mentally translate the jargon into plain English and see whether the claim still makes sense. “It draws limitless energy from the quantum vacuum” becomes “it makes energy from nothing” — and the plain version is much easier to evaluate.

Another frequent move is to blur a legitimate term with its fringe cousin. Physicists really do speak of “free energy” — a precise, unrelated thermodynamic quantity — and zero-point energy really does exist. Fringe claims trade on that overlap, borrowing the respectability of the real concept for a very different assertion. Knowing the honest definitions, as listed above, is the best defence.

For the ideas behind these words in context, see Free Energy & the Laws of Physics and Watching Critically. Standard references such as the Encyclopaedia Britannica on perpetual motion expand on the physics.