VAT is Value Added Tax that is levied in European and other countries on services and goods. In Australia, it is called GST (Goods and Services Tax).
In some countries, the rates of taxes are different for services and expenses. So CORE tracks VAT on expenses separately from VAT on services. It is denoted by VAT and VAT (E). You can, however, change the label from VAT (E) to VAT in the Custom Labels screen.
You might want to check out these articles on taxes in CORE: