Usage of word "meat"

Question

I am not a native English speaker and never lived in an English-speaking country, so I wonder how you would apply this word.

Would you apply the term "meat" to the following things?

1. Muscle tissue of a cow
2. Liver tissue of a cow
3. Brain tissue of a cow
4. Muscle tissue of other beasts (swine, goat, rabbit)
5. Muscle tissue of a bird (chicken, quail, turkey)
6. Muscle tissue of a fish
7. Muscle tissue of mollusks, such as oyster, squid, shellfish, snail
8. Tissue of polyp, medusa
9. Tissue of a sponge
10. Tissue of a mushroom
11. Tissue of a plant

Answer 1

It may seem rather odd, but you could apply "meat" to all of the above. Probably.

Wiktionary defines meat thus:

4. (uncountable) The flesh of an animal used as food.

5. (uncountable) Any relatively thick, solid part of a fruit, nut etc.

The first of these includes your points 1-7 fairly straightforwardly. Some vegetarians would quibble about whether fish was meat or not, but they are really drawing a separate(valid) distinction between fish and mammals.

By the time we're talking about polyps and sponges, most people wouldn't normally think of them in terms of eating. You could call them meat, but we usually don't.

Mushrooms and plants bring us to the second definition. If the mushroom or plant is substantial ("meaty"), we do sometimes refer to it as meat. It would usually be qualified in some way to make it clear that we weren't referring to animal meat, but the concept is well understood. It's moderately commonly used with reference to nuts and some fruit, rather less commonly with other plant or fungal matter.

Answer 2

So, this is actually a really good question, because exactly what counts as meat can vary a bit from person to person or situation to situation. For example, some people consider themselves vegetarians while still eating fish. Others say that no fish is allowed. So my best breakdown (open to comments):

Always meat:

• Muscle tissue of a cow
• Liver tissue of a cow
• Muscle tissue of other beasts (swine, goat, rabbit)
• Muscle tissue of a bird (chicken, quail, turkey)

Maybe meat:

• Muscle tissue of a fish
• Muscle tissue of mollusks, such as oyster, squid, shellfish, snail
• Brain tissue of a cow (I suppose if eaten, it could be considered meat, but I'm not familiar with brain eating.

Never meat

• Tissue of a sponge
• Tissue of a mushroom
• Tissue of a plant
• Tissue of polyp, medusa (unless these have something more akin to muscle than I'm thinking)

Edit: I'll also point out that meat can be used to describe the edible or substantial part of anything, e.g. the meat of the issue or he cracked the nut to get at its meat, but I assume that's not the sort you're referring to above

Answer 3

"Meat", unqualified, always refers to tetrapods (i.e. mammals, birds, reptiles, probably amphibians), as opposed to fish, arthropods or molluscs.

But with suitable qualification you can use "meat" to refer to any animal flesh: "crab meat" is common, as John Satta points out; and while I would not expect to see "tuna meat", I would not find it odd for somebody to refer to "separating the meat from the bone" when referring to tuna. (We do have "tuna steaks").

The use of "meat" for plant (or fungus) material, or for food in general, I would regard as archaic.

(Edited to generalise 'mammals' to 'tetrapods')