What’s the Difference Between a Table Olive and an Oil Olive?

What’s the Difference Between a Table Olive and an Oil Olive?
The quick answer is: nothing.  Many varieties are used for both oil and pickling and in some places where farmers primarily grow olives for oil, they pickle those varieties for eating, because that is all they have.  The same goes for areas where they primarily grow table olives; after farmers have filled their quotas for pickled olives, they crush the rest into olive oil.  The long answer is that table olives are larger in size and have a pulp-to-pit ratio that is very high, so that there is more “meat” to them.  They are also irrigated more, so that they get bigger and they usually have a lower oil content (around 10-12%, by fresh weight).  This means that olive oil olive varieties have a much higher oil content (can be as high as 25-30% by fresh weight).  They are also smaller in size in most cases. 
– Paul Vossen