good question..

"祖国，从字面意义上可以理解为祖先的国家。中华民国教育部解释，祖国即为祖籍所在的国家^[1]。但对于移民来说，祖国与母国是相对应的，祖国可能是指居住国，或侨居国，母国是指移民来源国，祖籍地所在的国家。^[2]《现代汉语词典》的解释，祖国就是自己的国家；而祖籍地所在的国家是祖籍国^[3]。马克思主义者则信奉“工人无祖国”，故中国共产党所称的祖国仅仅是统战用语。也有“商人无祖国”一说，用来说明商业行为的逐利性。"

http://zh.wikipedia.org/zh-cn/%E7%A5%96%E5%9C%8B

"A homeland (rel. country of origin and native land) is the concept of the place (cultural geography) with which an ethnic group holds a long history and a deep cultural association —the country in which a particular national identity began. As a common noun, it simply connotes the country of one's origin. When used as a proper noun, the word, as well as its equivalents in other languages, often have ethnic nationalist connotations. A homeland may also be referred to as a fatherland, a motherland, or a mother country, depending on the culture and language of the nationality in question."