A right-wing dictatorship (sometimes also referred to as a rightist dictatorship) is an authoritarianregime whose policy could be called rightist.
There are various definitions of the term "rightist." The broadest one includes all dictatorships that do not consider themselves communist. Those are usually pro-capitalist in economic matters and conservative in ideological ones.
The term fascist dictatorship is sometimes used interchangeably with the right-wing one. It is commonly accepted that Nazi Germany and the Kingdom of Italy were ruled by fascist governments at some points of their history; how it refers to other right-wing regimes is a question of further debate.