LSP (Language for Specific Purposes) phraseology differs in certain important regards from current research on LGP (Language for General Purposes) phraseology. This paper analyses the LSP sentence at both the semantic and the communicative levels, and comments on research and didactics of LSP. According to the author, terminology and LSP phraseology are closely related, to the extent that LSP phraseology can be considered as a main sub-discipline of terminology. Therefore, LSP phraseology can be, and should be studied applying terminological methods.