This article explores the complex relation between science and the media, and how scientific knowledge circulates outside the realm of specialists. It focuses on contextual definitions related to biological control (biocontrôle in French) in press articles, and the reader capacity to (re)build scientific information or knowledge based on media discourse. After introducing the emergence of the term in reference dictionaries and legal sources, we proceed to a twofold analysis of biocontrol definitions in the corpus (focusing on the relations of hyponymy and instrument/method). We first present a lexico-syntactic analysis of definitional cues that enable any non-expert reader to access definitions of the term. We then proceed to a semantic analysis of definitions, focusing on two different discursive strategies used by the media. Journalists either borrow reference terms (and synonyms) from official terminological sources or create ad hoc categories to simplify definitions with more accessible referents to press readers. Our goal is to show that the various categories involved in these definitions may hinder the understanding of the notion by the lay citizen (on the local scale), and potentially constitute an obstacle to well-informed decision-making about pressing issues such as environmental protection (on the global scale).