The term citizen (and thus citizenship) derive from the Latin term civis, and refer to a person recognized under the custom or law as being a legal member of a sovereign state. The Dutch and German term is burgher and was used in the same sense in South Africa under Dutch rule, becoming burger in Afrikaans. In English citizenship is often equated with nationality (as is burgerskap in Afrikaans), though the two terms tend to place different emphases.
The complexity of the notions citizenship and nationality have long posed severe problems in South Africa, often becoming a key element in the struggle towards democracy, since under Dutch and English colonial rule, as well as the Apartheid state, all Non-White or Non-European residents were excluded from citizenship of the country. This changed radically after 1994 and the acceptance of the South African Citizenship Act of 1995, to encompass all who live in the country. (See the website of the Department of Home Affairs at http://www.home-affairs.gov.za/index.php/civic-services/citizenship)
Nationality, equally complex in meaning - though perhaps a more emotive issue over the centuries - is often used as a synonym for citizenship in English, though there are distinct differences in emphasis in the definitions. (See for example "Nationality versus citizenship" under "Nationality" in Wikipedia).