A "content server" refers to a server that stores and directly manages content (information) provided to users. Its counterpart is called a "cache server," which stores copies of content managed by the content server. When a user requests the content, the cache server responds directly on behalf of the content server, reducing the content server load and overall network traffic.
However, within the Internet context, "content server" typically refers specifically to a "DNS Content Server." The Domain Name System (DNS) distributes responsibility for managing information needed for name resolution by segmenting domains into administrative units called "zones." Each zone is managed separately, distributing the necessary information for domain resolution across multiple servers.
These distinct administrative domains are called "zones." Thus, a "DNS content server" is specifically a DNS server that authoritatively holds and manages data for a particular DNS zone.