Kenneth G. Wilson (1923). The Columbia Guide to Standard American English. 1993.
PLAGIARISM
is the unethical quotation of anothers words or the unethical use of anothers ideas or data in such a way as to let the world conclude they are your own words, ideas, or data. With proper attribution, to quote anothers thoughts and words is appropriate; plagiarizing, however, is cheating, and it may break copyright law as well. Unconscious plagiarism does occur, but even that not everyone will excuse.