Skopos is a Greek word for “purpose”, and Skopos theory is an approach to translation, which was developed by Han J. Vermmer in Germany in the late 1970s. According to Skopostheorie, “one form of behavior is nevertheless held to be more appropriate than the other in order to attain the intended goal or purpose.”(Nord, 2001:27) The essence of the theory is that it proposes “the prime principle determining any translation process is the purpose of the overall translational action.”(Nord, 2001:27)
Skopos theory includes three principal rules: namely, the Skopos rule, the coherence rule (intratextual coherence) and fidelity rule (intertextual coherence). On the basis of Skopostheorie by Hans J. Vermeer, Nord summarized other academic thought and Criticism to the functionalist translation theory. She put forward the loyalty rule, which is the supplement to Skopos theory. The loyalty rule repaired the disadvantages and limitation of the Skopos rule, eliminate the translation at random and avoid the tendency which thinks translation is just target text writing.