This paper examines the concepts biological function (BF) and functioning as they are used in recent work on formal ontology and its applications in the biomedical domain. My purpose is not to offer an entirely new definition of BF. My objectives are: (1) to find out the basic features of BF mentioned in the reviewed articles; (2) to make more explicit the description of BF already present in those articles by relating it to an ontological category system; and (3) to emphasize the distinction between three cases of predication involving BFs, a distinction that should be taken into account when designing an information system. Hopefully, the results will make a contribution to the goal of providing a general, objective description of biological functions.