Fatherland is the land of one's "fathers", "forefathers" or "ancestors". It can be viewed as an ethnic/racial nationalist concept, if it refers to an area associated with an ethnic/racial group, such as a nation state.
The term "fatherland" refers to an anthropomorphized conception of certain lands. "Motherland" is another common, similar term. "Fatherland" is a translation of Latin "patria" (from "pater", meaning "father") and is related to terms such as patriotism. Such terms are, at least in their original meanings, examples of ethnic/racial groups loyalties often being compared to loyalties to relatives, which may be related to genetic similarities. See the article on Racial genetic interests, in particular the section Racial genetic interests: Ethnicity and territory.
Prior to World War II, such terms were used throughout the world and often with positive connotations, reflecting positive views on nationalism. For example, Wien Neêrlands Bloed, national anthem of the Netherlands between 1815 and 1932, makes extensive and conspicuous use of the parallel Dutch word.
More recently, such terms have become less common and are often viewed more negatively in many countries, due to increasing political correctness.