According to Lacan, Primary Identification is the identification of the Mirror Stage, which imitates the construction of the ideal I. Secondary Identification is the identification with the father at the final phase of the Oedipus Complex and the final formation of the ideal self. The subject uses this secondary identification to overcome the aggression that is a part of the primary identification. Although both forms of identification are characterized by the same imaginary mechanism, Lacan refers to the secondary identification as "symbolic identification" since it represents the completion of the subject entrance into the Symbolic Order. For Lacan, entering the symbolic order means the resolution of the Oedipus Complex, the acquisition of language and the final identification with the father.
see: Lacanian Terminology