Architecture for Product Master

Looking for feedback on creating an enterprise wide product master.
Is there such a concept?
What should it include?
Should it be only one table?
What if you are using multiple systems, some of which require their own table? (e.g. accounting system has it’s own product table which is not extendable but should use same product list a web store which is a home grown system)
Would you build web services that retrieve product data from 2 different systems / databases etc. (home grown + other)?
Thanks for your input.