I've really appreciated your answer however I've seen somewhere that "terderloin" meant contra-filé, is that correct too? By the way would you know the meaning for "sirloin"? Can it be a synonym to "lombo"?

Butcher-wise, sirloin is one part of a 'lombo' (loin), take a look at some meat cuts chart (cow-cuts-diagram).     The other part is the short loin.
Strip loin is the our “contra-filé”.
This way, if you have seen somewhere that tenderloin means ‘contra-filé’ don´t take their word for it.

Take heed of these details when you go to butcher´s!
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   Thus, the scheme is more or less this one:
    1.Loin (Lombo em geral)
    1.1 Sirloin         1.2 Short Loin (beef primals that feature cuts lowest in fat)
 
 
   a)Within the Sirloin
                          a.1) Sirloin Steaks - bifes de lombo
                           a.2) Top Sirloin - alcatra
                           a.3) Terderloin  - filé mignon
                           a.4) Tri Trip        - maminha
                           a.5) Strips and Cubes -   strips  (Strip loin is contra-filé) e pedaços de carne.
 
 
   b)Within the Short Loin
                    b.1)  T-bone     - corte com osso que reúne o contra-filé, com um pedacinho do do filé mignon.
                     b.2) Porterhouse  - corte com osso, também tem contra-filé e filé mignon, Mas é mais pedaçudo que o T-bone e tem um naco maior de filé. http://0001coisas.blogspot.com/2008/07/o-novo-mapa-do-bife.html

                     b.3) Club Steak -  um T-bone sem o músculo do filé mignon nele, é um pequeno bife da parte posterior do lombo (dizem a maioria dos sites).

                    b.4) Tenderloin – filé mignon.
                    b.5) Strip steaks – vi traduzido como bife de tiras (sendo às vezes bisteca)
                    b.6) Strips and Cubes

                    Then you go to rib (area) where you find:
                     Rib roast = Prime rib;
                     Rib steaks;
                     Rib eye (Delmonico); and
                     Roast or steak.