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What is the difference between classical particle and quantum particle?

I was thinking that we can distinguish between classical mechanics and quantum mechanics by changing our length scale. But I don't understood in what way or on what parameter we differentiate between classical particle and quantum particle.

you take one proton or neutron and say that it quantum particle, but when you make a solid out out of proton and neutron you say we have a classical body.

just a matter of size, I think?

just only size determines whether something will be a classical or quantum particle? or some inherent deep meaning?

There are no Question discussing Quantum and classical particle and can pose doubt to a beginner.

crabNebula
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The quantum and classical particles are governed by different principles and described by different equations. However, in a certain limit a quantum particle behaves like a classical one, which is expressed by the Eherenfest theorem.

The relationship between quantum and classical is somewhat complex, as discussed, for example, in this thread.

Update
In response to the updated question, let me first clarify the terminology.

  • Particle may mean different things, depending on the context. It can mean a point like object, i.e. an object whose internal structure is not essential for the problem that we are solving. Thus cars and stars are often treated as particles in mechanics. Particle may also mean an elementary particle - a special class of physical entities, such as electrons, protons, neutrons, photons, etc.
  • When speaking of classical and quantum one also has to distinguish between the actual physical world and mathematical formalisms that we use to model it. All the physical objects in this world are quantum and relativistic, but in many cases simplified classical description is quite appropriate for practical purposes.
  • Finally, it is necessary to mention that classical has special role in the sense that it is the limit most familiar to us from our conventional everyday experience, this is where we have most "intuition".
Roger V.
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You seem to have the idea that quantum mechanics is simply given a different name because it is talking about smaller scales, but the truth is that the entire world is quantum mechanical including the macroscopic world. Quantum mechanics is a qualitatively different update to classical mechanics. We just didn't notice that we needed a better description of the world until we looked at small scales, since this is where quantum effects are most noticable.

Jeff Bass
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Quantum particle has following properties: 1- always a microparticle like electrons, atoms and molecules. 2- A Free particle is not a quantum particle, Latter is always bound. 3- A quantum particle is not stationary. It has a confined movement/motion(translational,vibrational etc)

Oreo
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In classical physics "a particle" is the approximation of the motion of an extended classical object by the motion of its center of mass, i.e. we are neglecting rotations and internal degrees of freedom. The most often used particle approximation in classical physic is the in the Kepler problem where both the sun and the planet are being treated as particles. This approximation is useful and valid for planets like Earth, but it is already false for e.g. the Moon, which is tidal-locked to Earth.

What people call "particle" in quantum mechanics are actually quanta of energy, momentum, angular momentum and charge. It is a gross misnomer and leads to endless misunderstandings about the structure and meaning of quantum mechanics. There are no "particles" in quantum mechanics and it is not a theory of "small objects". Quantum mechanics is an ensemble theory of reversible and irreversible energy transfer between systems. The individual irreversible energy transfers are called "quanta" and depending on the experiment their average behavior can show wave and particle-track like features.

FlatterMann
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In quantum physics the behaviour of a system depends on what happens in all of the states it could be in. For example, if you send a single photon at a pair of double slits the resulting interference pattern will depend on whether you put a lens on the paths between the slits and the detectors. Quantum interference and quantum entanglement both depend on that property of quantum systems.

If you copy information out of a quantum system while it is undergoing interference that will tend to suppress the interference: this effect is called decoherence:

https://arxiv.org/abs/1911.06282

Classical physics is what you get when decoherence effects are strong enough as they are for the objects you can see. Everything you can see is having information copied out of it much faster than the timescales it takes to change much, e.g. - there are lots of air molecules and photons interacting with me as I type this and they're doing it much faster than I can type.

Classical particles are just decoherent quantum particles.

alanf
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