Definition - What does OpenDNS mean?
OpenDNS is the name of a Domain Name System (DNS) service as well as of the company that provides that service. The OpenDNS service extends the DNS by incorporating features such as content filtering and phishing protection. It is also touted as faster, more reliable and having zero downtime because of its global network of DNS servers that ensures that, if one or two servers are down, the others can still carry the slack.
Techopedia explains OpenDNS
OpenDNS, the company, provides a DNS service a step above those being provided by Internet service providers (ISPs) around the globe. DNS is an integral part of the World Wide Web that allows both humans and computers to understand each other when it comes to Web addresses; humans can identify words easily (domain names), whereas computers rely on numerical values (the IP address of a website). DNS is a directory service, and DNS servers are essentially lookup tables containing the associations between domain names and their respective IP addresses. The DNS server essentially points the user's request toward the correct address of the computer/server that hosts the website being requested.
OpenDNS extends the DNS service by improving the efficiency of the system by adding more servers across the globe that can detect the nearest server to the user and use that to serve the user's requests. This improves the efficiency since regular ISP-driven DNS servers are few and usually far away from most users. It also adds another layer of security through PhishTank, its anti-fishing service that takes the guesswork out of distinguishing phishing websites from the originals, and now also offers a cloud-delivered network security product called Umbrella. Added parental controls also allow filtering of websites and website contents. OpenDNS is free for its basic services, but advanced services targeted for businesses and larger institutions have subscription fees.