Ontology / Taxonomy Help

After today's lecture from Dr. Fridsma on Ontologies and Taxonomies, I left rather confused and have been searching for some concrete examples to help clarify.  I understand at a high level that taxonomies have a hierarchy and ontologies don't and they are important to developing a good data model in the end.  In my simple way of thinking, ontologies are the unique, defined terms to describe items be used for a specific purpose or within a specific domain.  Taxonomies would be a way to categorize and search for those items.  In the wine example, the top level of the ontology would be "wine" but then you could create subclasses of "red", "white", "rose"  or you could create subclasses of dry, sweet, etc.  From there you can drill further into the flavors, and name within those areas, etc.  The entire list (I think) would represent the ontology with various interlinking between classes.  A taxonomy would be a way to group and search those items. 

I'm a little confused with defining ontology versus vocabulary.  To me they seem like the same thing so I'm continuing to search for examples.  SNOMED is an example, I think of ontology but I think it also could be described as a set of standardized vocabularies of medical conditions.

Even after reading a lot more and searching, I'm not really clear on the differences.  I'm going to post a couple of references I had found.  It's interesting to note in my further searching there hasn't been added clarity provided.  What we heard today in class is very similar to what you find on the web but if anyone finds a reference with good, simplistic examples, it would be helpful.

#1:  More detailed example of the wines from the lecture today;  http://protege.stanford.edu/publications/ontology_development/ontology101-noy-mcguinness.html

# 2:  Indepth discussion on this entire topic (286 pages) for anyone wanting to get really deep:  http://www.omg.org/docs/ad/05-09-08.pdf

#3:  For Taxonomy - here is the Health Care Provider Taxonomy Code used by CMS / Medicare:
http://www.wpc-edi.com/taxonomy


Posted by :  Debbie Carter