Delve is a powerful search engine that looks across all of the content in your network, checks to make sure you have access to it, and then presents it to you. It is powered by the Office Graph, which uses machine learning techniques to map all of the activities taking place across email, OneDrive and SharePoint.

Navigate to https://support.microsoft.com/en-us/office/what-is-delve-1315665a-c6af-4409-a28d-49f8916878ca for additional information.  

An acronym for Domain Name System.  DNS is how the internet converts alphanumeric names like www.google.com into numeric IP addresses like 192.168.1.101 so that a server can return the website associated with that IP address when that name is searched.