The meaning of RET 2 in assembly

Yes, but ret 2 also removes 2 bytes of parameters from the stack. Presumably, your function was called like:

push some_parameter
call Function

At this point, a cdecl function - a "caller cleans up" function (Generally used by C) - would require add sp, 2 to "clean up the stack", removing the parameter. Such a function would end in a plain ret.

A stdcall function, which is what you've got, is a "callee cleans up" function (used by Windows APIs, for example) doesn't require the add sp, 2 - it has been done by the ret 2.

If you're not aware of it, call puts the return address on the stack (and ret pops it off), so you can't just pop to get the parameter inside your function.

Lets say I have a procedure to add two words and leave the sum in EAX. The words are arguments I want to pass to the procedure on the stack. i.e:

push word1
push word2
call addtwob

The procedure would look something like:

addtwob proc

push ebp
mov  ebp,esp
mov  eax, [ebp+6]    
add  eax, [ebp+8]
pop ebp
ret 4

Endp

[ebp+6] and [ebp+8] address word2 and word1 on the stack. ret 4 just returns like usual but then adds 4 to the stack pointer (esp) so you don't have to pop word2 pop word1 off the stack after returning from the call, therefore it cleans/balances the stack without needing to pop the previous pushes.