Plagiarism refers to representing someone else's text, or part of a text, pictorial presentation or translation as one's own work. Both copying direct quotations and adaptation (paraphrasing) from another author's work is considered plagiarism. Also, reusing one's own text from previous work is considered plagiarism (self-plagiarism). Plagiarism is often unintentional, due to ignorance or negligence.
Plagiarism is a violation of responsible conduct of research. Other forms are misappropriation, fabrication and falsification. More information on Responsible Conduct of Research (RCR) can be found in the RCR Guidelines compiled by Finnish Advisory Board on Research Integrity (TENK).
Haaga-Helia takes a serious approach to plagiarism (Degree Regulations) and uses Turnitin plagiarism check software to track it. Your teacher will inform you if a course assignment is to be submitted through the plagiarism check. Theses are always checked using Turnitin.
Both methods require appropriate referencing!