Cloud security refers to the measures and protocols implemented to protect data and resources stored or transmitted via cloud computing platforms. It aims to safeguard sensitive information, prevent unauthorized access, ensure data privacy, and mitigate various cyber threats like data breaches, malware attacks, and unauthorized data modification. Effective cloud security implementations involve encryption, access controls, multi-factor authentication, regular monitoring, and robust security policies to ensure the integrity and confidentiality of cloud-based data and applications.