Answer:
Nationalism is an idea and movement that promotes the interests of a particular nation, especially with the aim of gaining and maintaining the nation's sovereignty over its homeland. Nationalism holds that each nation should govern itself, free from outside interference, that a nation is a natural and ideal basis for a polity and that the nation is the only rightful source of political power. It further aims to build and maintain a single national identity, based on shared social characteristics of culture, ethnicity, geographic location, language, politics, religion, traditions and belief in a shared singular history, and to promote national unity or solidarity. Nationalism seeks to preserve and foster a nation's traditional cultures and cultural revivals have been associated with nationalist movements. It also encourages pride in national achievements and is closely linked to patriotism. Nationalism is often combined with other ideologies such as conservatism or socialism.
Sectionalism is loyalty to one's own region or section of the country, rather than to the country as a whole. Sectionalism occurs in many countries, such as in the United Kingdom, most notably in the constituent country of Scotland, where various sectionalist/separatist political organizations and parties have existed since the early 1920s, beginning with the Scots National League. Today, Scottish sectionalism is most strongly associated and advocated by the Scottish National Party (SNP), which can be described as both sectionalism and separatist. The SNP advocates for both Scottish independence and more autonomy for Scotland while remaining a part of the United Kingdom.