Definition of Duplicate Content?
 

"duplicate content": your content is being shown on multiple pages locations on and off your site and they don't know which location to show. Especially when people start linking to all the different versions of the content, the problem becomes bigger. This article is meant for you to understand the different causes of duplicate content, and to find the solution for each of them.
You can compare it to being on a crossroad, and road signs are pointing in 2 different directions for the same final destination: which road should you take? And now, to make it "worse" the final destination is different too, but only ever so slightly. As a reader, you don't mind: you get the content you came for. But a search engine has to pick which one to show in the search results, as it doesn't want to show the same content twice.

Duplicate content are those content which are repeated and submitted regularly.

When a content used on more then 1 or 2 sites and google notice it will count as a duplicate content

Hey,
We must avoid duplicate content to increase our website's value. Content which gets repeated over time is known as duplicate content.

Duplicate content is the content that is already published on a different webpage and is indexed by search engines.