Plagiarism is Stealing
Each day we take ideas from others without citing the original source. When we repeat the phrase "Dr. Livingstone I presume" or "elementary my dear Watson" in casual conversation, we rarely pause to give credit to Stanley or Doyle. In academic research, intentionally or unintentionally taking someone else's work and passing it off as your own is plagiarism--and plagiarism is stealing. If you have any doubts about a phrase or idea that you'd like to include in your own research, speak with your professor.