Are Dark Matter and Antimatter "states" of matter? What broad category do these fall into?

Question

This question is more to do with what matter is and what matter is not. We know that there is something called matter, which is basically everything we see around us. 17 fundamental particles make up all matter around us. There's also antimatter, which is made up of 17 anti-particles. Then there's also Dark Matter, something which is debated on a lot. It's unclear what it is. According to Google, it is "composed of particles that do not absorb, reflect, or emit light, so they cannot be detected by observing electromagnetic radiation." Further, Dark Matter has been hypothesized to have anti- counterparts, anti-dark matter.

My question is whether all of these kinds of "matter", these constituents of the universe, are really matter at all. If not, what is the broad category that all of these "types of matter" fall under? I've met many people who think that dark matter and antimatter are "states" of matter, and I'm not entirely sure if this is true.

Answer 1

The word "matter" has had a variety of technical usages over time, and its meaning at this point is context-dependent. Sometimes people use matter to mean fermions, in contradistinction to bosons. Sometimes people use the word to mean something that's not antimatter.

My question is whether all of these kinds of "matter", these constituents of the universe, are really matter at all.

It depends on context.

I've met many people who think that dark matter and antimatter are "states" of matter, and I'm not entirely sure if this is true.

This is a natural way to think about it in quantum field theory, where an antielectron can be modeled as an electron going backward in time.