Privacy is a critical concern in the digital age, especially with the rise of AI technologies. Despite its importance, privacy lacks a universally accepted definition, making it a complex and multifaceted issue. This paper offers an overview of privacy conceptualisations in philosophy, law, and social sciences. By integrating these disciplinary perspectives, we propose a composite, operational definition of privacy. Having such a definition is particularly relevant to AI governance through regulations due to the textual nature of the law. The interdisciplinary approach of this paper aims to bridge theoretical insights with practical implications for privacy protection in the era of AI.