In most conservation programs that include public participation, the word "biodiversity" is used. However, many variables influence the public understanding of the term and determine what biodiversity means to local stakeholders. Those representations of the concept must be addressed and included in conservation actions. We asked 47 local stakeholders in a biosphere reserve (BR) located in a biodiversity hotspot in South America, for whom the conservation of biodiversity is not the main focus of interest, to explain how they understand the term "biodiversity." Twenty-two different definitions were provided, ranging from purely ecological concepts to the human dimension. Although the diversity of animals and plants was the most frequently mentioned concept, the variety of concepts that emerged suggested that more explicit examples of social constructions must be considered in public participatory projects and environmental education programs. Actors living in a close relationship with nature provide a greater diversity of elements in defining biodiversity, visualizing ecological but also instrumental values.