Plagiarism means whether your article is unique or not. If a part of the article is copied from somewhere, then it is plagiarized content.
This is incorrect.
Plagiarism is the representation of another author's language, thoughts, ideas, or expressions as one's own original work.
Thus if part of an article is copied from somewhere but attributed (even misattributed) to someone else it is, by definition, not plagiarized.
Thanks for pointing this out. This is actually just a typo! It was a year ago and I can't remember why I wrote like this! Because I am well aware of what plagiarism is.
Edited! Thanks again.