so what exactly is an instruction?
1.) is an opcode considered an instruction?
2.) is an operand also considered an instruction?

3.) is a combination of an opcode & operand makeup a legal "definition" of an instruction?

MOV is an instruction
an Operand is "what" to operate on, so in the below sample eax and ecx are the operands

mov eax, ecx

and the opcode for the above mov would be 8B and the whole opcode for mov eax, ecx would be 8BC1 (Helps to have the Intel and AMD manuals)

Mov is just a mnemonic for an opcode, yes an opcode is an instruction that tells the cpu what to do. Yes a combination of a valid opcode/mnemonic and valid operand(s) make up an instruction