Thomas Aquinas’s account of the semantics of names is based on two fundamental distinctions: the distinction between a name’s mode of signifying and the signified object, and that between the cause and the goal of a name’s signification, i.e. that from which a name was instituted to signify and that which a name actually signifies. Thomas endows names with a two-layer signification: names are introduced into language to designate primarily conceptions of extramental things and secondarily the particular extramental things referred to by such conceptions. On such a ‘conceptualistic’ account of names’ signification, Thomas recognizes that a generic acquaintance with external things is a sufficient condition for imposing names to signify things. Following this intuition, Thomas at times dwells on the role that pragmatic factors such as the common usage of names by a linguistic community (usus loquendi) and the speakers’ intention (intentio loquentium) play in explaining both the formation and semantic function of conventional language. This paper will focus on what Thomas had to say about such factors.