Plagiarism is using other people's words or ideas in your own work - without making it clear to the reader/teacher that the words or ideas have been copied. If you find some information in a book or on the internet and use it your own writing, you must state the source. If you do not, then you have plagiarized.
What is wrong with plagiarism?
Plagiarism is a kind of cheating or theft. Like all offenses, some kinds of plagiarism are more serious than others. The student who copies one or two short phrases from another writer without referencing them is guilty of laziness or forgetfulness, or both. Compare him, however, with the student who downloads a complete essay answer from the internet and turns it in as his own work. He has committed a far more serious act of plagiarism, and in many academic institutions would be expelled.
How do teachers know that students have plagiarized?
Teachers can usually tell very quickly if a student has plagiarized, especially the ESL student whose writing contains language of unusually high quality: perfect accuracy, rare vocabulary, complex sentence structure, etc. There are also websites that teachers can use to investigate students suspected of plagiarizing whole essays or parts of them.
How can plagiarism be avoided?
Having understood what plagiarism is, it is now important to learn how it can be avoided:
Reference all sources.
Clearly, each source that a student has used in doing a piece of writing must be appropriately referenced according to its type: book, website, periodical, etc. There are clear and detailed rules for writing a bibliography (references), and the best modern way is to use a computer tool. The online bibliography-maker NoodleTools is recommended for school-age students.
Use direct quotations. Copy the words you want to use into your own writing, put quotation (speech) marks around them, and include the appropriate references. More information.
Learn how to paraphrase. Rewrite the passage (paragraph, sentence or phrase), idea for idea, in your own words. You must still reference the book or internet article at the end of your work as the source of your ideas, but you don't need to use quotation marks.
Take good notes To gain a good grade for a piece of writing it is certainly necessary to avoid plagiarism, but it is not enough. Your teacher will not be happy with a piece of work that consists only of direct quotes or paraphrased passages, even if these are carefully referenced. It is important for you to formulate information, ideas, etc. in your own words. The best way to do this is to take good notes from the source you are using and use only those notes when sitting down to do your writing. More about taking good notes.
Take cross-language notes
Taking notes in your own language, which you then convey into English sentences, is an even more effective way of ensuring that what you have written is entirely yours in terms of written expression, and therefore not plagiarised. Alternatively, you can research in your own language, and write notes in that language or in English. Of course, you still need to correctly cite the source of your information. More about cross-language note-making.