Other forms: contesse; contessas
Contessa is the title given to an Italian noblewoman whose husband is (or was) a count. She can also hold the title on her own. If Count Dracula had been a woman and Italian, he would have been Contessa Dracula!
The word contessa is borrowed from Italian, but its similarity to the English word countess is pretty obvious. Europe and Britain had different titles for their nobles, and a European count had the same rank as a British earl. So in Britain, a countess is the wife or widow of an earl. For those not familiar with this history, it can be confusing to keep all these ranks straight! In Italy, contessa is also used as a title of respect for any lady.