1. The action or practice of taking someone else's work, idea, etc., and passing it off as one's own; literary theft.
2. A particular idea, piece of writing, design, etc., which has been plagiarized; an act or product of plagiary.
In the United States, plagiarism is taken very seriously. You need to be aware of the requirements for giving credit for the contributions of others. This may be quite different from your home country, where writings and information may be considered to be "owned" by everyone.
For more information, please refer to the LibGuide on Plagiarism. You can access it by clicking on the link in the bottom box to the left.