1828 Webster's Dictionary
National character; also, the quality of being national, or strongly attached to ones own nation.
1911 Encyclopedia Brittanica
A somewhat vague term, used strictly in international law (see International Law, Private) for the status of membership in a nation or state (for the conditions of which see State, Allegiance, Naturalization, Alien), and in a more extended sense in political discussion to denote an aggregation of persons claiming to represent a racial, territorial or some other bond of unity, though not necessarily recognized as an independent political entity. In this latter sense the word has often been applied to such people as the Irish, the Armenians and the Czechs. A "nationality" in this connexion represents a common feeling and an organized claim rather than distinct attributes which can be comprised in a strict definition.
Nationality is a legal relationship between an individual person and a state. Nationality affords the state jurisdiction over the person and affords the person the protection of the state. What these rights and duties are varies from state to state.
(As noted by Vox Day.)