Definition
Means any structured set of personal data which are accessible according to specific criteria, whether centralised, decentralised or dispersed on a functional or geographical basis
Source
Point (6) of Article 4 of Regulation (EU) 2016/679 of the European Parliament and of the Council of 27 April 2016
Link
https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:32016R0679