What is the actual relation between assembly, machine code, bytecode, and opcode?

Question

What is the actual relation between assembly, machine code, bytecode, and opcode?

I have read most of the SO questions about assembly and machine code, such as this,

Answer 1

Is there some sort of standard reference that lists out all of those numbers, and what they mean, for whatever architecture you are on, and how each set of numbers maps to each assembly instruction?

Yes, though they can be very complex. Also, due to the prevalence of assemblers and compilers, they're also sort of hard to find, because pretty much nobody uses them.

Relation Between Assembly and Bytecode

• Machine code - One or a series of values read into a CPU. Each number is an "instruction" or "opcode", and may be followed by one or more parameters to act on. In the linked code, 13 tells the processor to push a string onto the stack.
• OpCode - The value for a command: In the sample, the opcode for pushing a string is 13.
• Assembly - human readable instructions for a CPU's internal machine code. Pretty much always one assembly instruction per machine code instruction. In my code that you linked to, the "assembly" instruction PushString maps to machine instruction 13.
• Byte Code - Since each processor uses a different machine code, sometimes programs compile to a machine code for an imaginary "virtual machine", and then have a program that reads this fake machine code and executes it (either via emulation or JIT). Java and C# and VB all do this. This "fake" machine code is called "byte code", though the terms are often used interchangeably.

I should note that the bytecode instructions used in this post and in my other post that you linked to are simplified extracts from a proprietary byte code I work with at my company. We have a proprietary programming language that compiles to this bytecode which is interpreted by our product, and some of the values I mentioned are real bytecodes we actually use. 13 is actually pushAnything with complex parameters, but I kept things simple for the answer.