A cloud service is a remote system that delivers features, storage, or account functions over the internet. In practice, it may handle sign-in, sync settings across devices, store files, process notifications, or run smart-home features that are too heavy or convenient to keep fully on the local device.
Cloud services matter in cyber security because they move data and control outside the physical device and into a provider-managed environment. That can expand the attack surface: if an account is stolen, a token leaks, or the provider is misconfigured, attackers may reach messages, backups, cameras, or connected devices. Defenders reduce risk with strong authentication, least-privilege permissions, careful review of what data is sent off-device, and clear separation between local functions and remote account services.