Plagiarism means using someone else's words, ideas, images, data, code, or structure without giving proper credit. It can happen on purpose, but it can also happen accidentally when sources are handled carelessly.
Common examples
Copying text without quotation marks, paraphrasing too closely, submitting another person's work, using uncited AI or web content against class rules, or copying a source's structure without credit can all be plagiarism.
How to avoid it
Take careful notes, separate your own ideas from source material, use citations, quote exactly when needed, and explain ideas in your own words.
The safest habit is simple: when a reader should know where information came from, cite it.