The country of residence is the country in which a natural person has his/her permanent residence or place of habitual residence, i.e. the country in which a person lives for a continuous period of more than six months per year. The country of residence is used, for example, to determine tax liability or jurisdiction.
A taxpayer is generally subject to unlimited taxation in his/her country of residence. The counterpart to the country of residence is the source country.
Source: Wikipedia, edited (only available in German)