Is a word [letter] and [scripture] in 2 Peter 3:16 the same meaning? 2 Peter 3:16 


  He writes the same way in all his letters, speaking in
  them of these matters. His letters contain some things that are hard
  to understand, which ignorant and unstable people distort, as they do
  the other Scriptures, to their own destruction.


I mean, when Peter said "his letters" ---> Did Peter mean [his Scriptures] ?



As I'm from a non-English speaking country, this is quite confusing for me. Because in our language words, a Scripture is a Bible - while a letter is not a Bible. And of course, in this modern time - no one will say "I'm writing a Bible" :).

Illustration : 
Suppose Peter is writing for his fellow Christians. 
Someone phone him "Hi Peter, what are you doing ?".  
Peter answer "I'm writing a scripture". 

What will be in the caller's mind ? 
A. Peter is writing a Bible 
B. Peter is writing a letter (not a Bible) 

Thank you.
In English, the literal meaning of the noun "scripture" is "something written". When Peter uses the word in the passage you cite, he probably is using "Scripture" to refer to a specific set of writings accorded esteem as "holy", but in Peter's case, he is not referring to the Christian Bible, but to the books considered Holy by the Jews, that is, the Word and the Prophets. In your illustration, Peter would be more likely, if someone came to his door and asked what he was doing, to answer simply "I'm writing."

Now in the case of the passage you cite, "letter" refers to a particular type of writing, a written message intended to communicate a message to a person or group of people, in the same sense that one today might write a letter to an individual who is distant, and for whom communication by other methods is not desired or feasible. Paul's letters are particular kinds of writing, but are still scripture. Peter here is drawing a particular kind of equivalence between the letters Paul wrote, with the Hebrew Bible.