The justified definition and classification of perlocution, a core concept in the Speech Act Theory, is conducive to the perfection of the theory as well as the settlements of the conceptual discrepancies.To this end, the paper first reviews the literature on the categorization of perlocution, and argues that the classification is necessarily based on a tenable definition of perlocution.Based on a thorough analysis of connotations of "speech is act", perlocution is defined as the act of affecting and changing the communicative context, performed by the speaker with a locution carrying an illocution.Finally, following reconsideration of the triple senses of locution, three senses of perlocution are identified and exemplified, namely, phonetic, phatic and rhetic perlocutions.