No, origin is not a special branch in GIT.
Branch origin is similar to branch master. It does not have any special meaning in GIT.
Master is the default name for a starting branch when we run git init command.
Origin is the default name for a remote when we run git clone command. If we run git clone -o myOrigin instead, then we will have myOrigin/master as our default remote branch.Read the full book at www.amazon.com