For most legal jurisdictions, the terms ‘nationality’ and ‘citizenship’ are effectively interchangeable, however, due to the complexity of the UK’s nationality laws, this is not the case. Nationality refers to the status of a person as belonging to a state, whereas citizenship refers to the holding of a bundle of civic rights, generally including the right to live and work in the territory of the state concerned. Read more.
UK Citizenship vs UK Nationalities – Know Your Status
Fragomen's Grace Ding explains citizenship vs. nationality in the UK given their complex nationality laws.