Hi Mark ,
It's not almost a lookup , it is a lookup.
Set up your relationship table , where in one column , you have the words "Restaurant" , "Hardware" and so on. In the next column , have the corresponding categories , such as "Dining" , "Home Improvement" and so on. Assume this table is called the Category_Table.
Now , if your words such as "Restaurant" , "Hardware" are in column A , starting from cell A3 , then in column B , starting from cell B3 , have the following formula :
=VLOOKUP(A3,Category_Table,2,FALSE)
Narayan