What is DNS in the networking

A DNS(Domain name system) server translates a domain name(As if facebook.com) into a numerical IP address that is used to path communications between nodes. DNS (acts like a translator), understands to only IP address- By IP we can open anyone website. But the IP address of all website can not remember, hence have created to DNS. To increase performance, DNS saves to (Modified data or translated data) in the system for a certain amount of time. Of which, is called Cache. Until that cache doesn't expire in the system, till then website will open by using that cache.