ICBO is the International Conference on Biomedical Ontology, held this year in Buffalo, NY. Ontologies can be defined in various ways; I prefer to think of them as formal systems for describing domain concepts and their instantiations. Topics include: Ontologies for Chemistry and Molecular Biology, Cellular and Anatomical Ontologies, Disease Ontologies, Clinical Ontologies, and IT topics such as computing with ontologies and getting ontologies to work together.
Much of the effort in this area is geared towards extracting biomedical data from various sources and representing it in a computable form. Doing this requires the ability to both represent universal truths about biological systems and describe instances of these truths as applied to individual cases. One can think of ontologies as playing a key role in the irresistible move from dispersed documents to linked data.
Biomedicine contains many difficult modeling problems, e.g., the classification of lipids, where the nomenclature is currently very heterogeneous, and based upon graphical concepts. Even attempts to axiomatize chemistry are full of pitfalls for the unwary, e.g., it doesn't make much sense to talk about a molecule having a boiling point, however tempting it might be to attach the information there, since heat is something that applies to substances, rather than individual molecules. Similarly, the modern view of RNA has changed from its taking a passive role in gene transcription to a more active role in gene expression.