Holland or the Netherlands?
The official name of the country is the Netherlands - 'Low Lands', a country where more than half of the population live below sea level.
A few centuries ago, the province of Holland (now the North and South provinces) was econamically the strongest of all the other Dutch provinces, and the one from which virtually all foreigh trade originated. Most of the Dutchmen that foreign traders dealt with were Hollanders, so from Holland.
Therefore and because of its history, when talking about the Netherlands, Holland became the accepted way of referring to the country and its people. However, the Dutch people who are not originated from or living in the North or South provinces may not like to be referred as Hollanders