In the First Logical Investigation Husserl maintains that in order to achieve a phenomenological, subject-related and yet non psychological theory of meaning, one must begin by drawing an «essential distinction » between expressive and indicative signs. As a consequence, Husserl maintains that «sign » is an equivocal term. In this paper, I will set out and elaborate the historical background of this claim tracing it back to Bolzano’s theory of signs and situating it within the broader context of the Brentano’s School. This will lead me to (1) flesh out the role of semiotics in Husserl’s critique of psychologism and (2) emphasize its meaning and scope in contrast with the widespread contention according to which «sign » is an univocal term whose structure can be captured by the medieval formula «aliquid stat pro aliquo » .