Just as beauty is in the eye of the beholder, so is "advanced" in the mind of
the person who wrote the requirement.
dhstein has probably given as good a list as any, but...
for some people, "advanced" might be the ability to build and use more
complex formulas than simply =A1+B4. It might include the ability to create
V/HLOOKUP() formulas, reference data on other sheets or in other workbooks,
or create a query to return data from an external source. Or it might refer
to having a good working knowledge of special worksheet functions such as
financial and/or engineering functions.