Both natural objects and artifacts have been studied from a variety of perspectives by the different sciences. One issue that has so far resisted philosophical and ontological investigations is the definition of a general notion of function capable of making sense of the functions attributed to natural objects, such as biological organisms, as well as of the functions attributed to artifacts, such as (designed) tools.

The paper starts from the notions of role and context to study a definition already used to define artifact functions. The clarification of types of functional contexts and of the role of intentionality in defining function leads to a new proposal that applies to functions of natural objects as well as of artifacts. Finally, we evaluate our proposal against some desiderata discussed in the literature.