Is Wikipedia a reliable source?

Because Wikipedia is easily edited, it's not considered reliable. But it is commonly used and can be useful as a starting place for research, especially for finding the sources that are cited in each article.

Wikipedia is not a reliable source. It usually uses reliable secondary sources, which vet data from primary sources. If the information on another Wikipedia page (which you want to cite as the source) has a primary or secondary source, you should be able to cite that primary or secondary source and eliminate the middleman (or middlepage in this case). Always be careful of what you read; it may not consistently be reliable because work submitted to Wikipedia can be edited, used, and redistributed—by anyone. As indicated by WP:CIRCULAR, which is part of the Verifiability policy, neither articles on Wikipedia nor websites that mirror Wikipedia can be used as sources, because this is circular sourcing. An exception to this is when Wikipedia is being discussed in an article, which may cite an article, guideline, discussion, statistic or other content from Wikipedia or a sister project as a primary source to support a statement about Wikipedia (while avoiding undue emphasis on Wikipedia's role or views, and inappropriate self-reference).

See also[edit]

Wikipedia:Wikipedia is a tertiary source

Wikipedia:Manual of Style/Self-references to avoid

Wikipedia:Verifiability#Wikipedia and sources that mirror or use it

Wikipedia: identifying reliable sources

Wikipedia has some accurate information, and many many big holes. Its great problem is not so much innacurately placed information, for inaccuracies can be corrected. But where nobody has bothered to add important but perhaps unexciting details to a page -- then it can seem to emphasize only those elements of a matter which do spark some interest, even if they are comparative trivialities.

your cousin is half right and half wrong

yes anybody can add information to wikipedia ... but... if that information is not verifiable or is in any way incorrect it will be edited and changed

wikipedia is the MOST reliable source of information available on the web

it is the most used site of any other site on the web

For the most part it is fairly reliable. Yes, anyone can post what they want and edit things, but generally the community is fairly self correcting - there are enough people who know the truth who correct errors which are made. As in all things, however, for something important and where the most accurate information is critical, NEVER trust just one source.

Your cousin is almost right. It is not more than a secondary or tertiary source. If you pay attention to Wikipedia's articles about itself, it'll tell you all that and more.

Nope its not a reliable source. Never use it for assignments or any of your academic work cuz you'll fail with flying colours.