nomenclature of some organoselenide moieties
Based on usage:


Selenenylate is a verb. It means to attach a selenium group to an organic compound - See this passage from Comprehensive Organic Synthesis: Selectivity, Strategy, and Efficiency in Modern Organic Chemistry, Volume VII 



  The analogous morphinoselenamide has been shown to selenenylate the $\alpha$-ketoester...



Selenolate is a noun. It is the $\ce{RSe-}$ anion, especially in ionic or coordination compounds. See various usage at the links in this Google search