You can find a full definition of copyright on the U.S. Copyright office website and how it relates to international copyright relations. Here is a short description:
Copyright is a legal concept that gives the creator of an original work exclusive rights to it. The copyright holder has the right to choose if anyone else can use, adapt or resell their work and have the right to be credited for that work.
Only the copyright holder of a work may do the following:
The creator of a work retains copyright to it even if they don't expressly tell you so.
One Strike Violations include, but are not limited to:
Penalty: Any author responsible for such a violation will have their account DISABLED immediately. Any cash on the account will be held indefinitely and the user will not be eligible for a new account on the site.
Appeals: Appeal can be made for reinstatement by contacting support to discuss the matter, however any author seeking reinstatement must provide sufficient cause.
In recognition that some areas of copyright are a little grey, these violations have a less severe penalty. Nonetheless they will lead to action if the author does not respond and/or take appropriate measures.
Warning Violations include, but are not limited to:
Penalty: A warning will be issued by email. Offending files will be immediately removed from Envato sites and earnings from those files held indefinitely. Further violations will results in escalation in the penalty.
Appeals: Appeal can be made for a file by contacting support to discuss the matter.