Orthodox means following traditional or established beliefs and practices, especially in religion. When someone describes their beliefs as orthodox, they mean they stick closely to the original teachings rather than creating new interpretations or making big changes.

In Christianity, Judaism, and Islam, orthodox believers follow the long-standing practices and interpretations of their faith. The Eastern Orthodox Church, for example, maintains worship traditions that go back nearly 2,000 years. In Judaism, Orthodox Jews carefully observe traditional religious laws about food, prayer, and daily life that have been passed down through generations.

Outside religion, orthodox can describe any conventional or widely accepted way of doing things. An orthodox approach to teaching math means using tried-and-true methods rather than experimental techniques. A chess player might use an orthodox opening, meaning a classic, well-established strategy rather than something unusual or risky.

The opposite is unorthodox, which describes something unconventional or surprising. An unorthodox solution to a problem might work brilliantly precisely because it doesn't follow the usual pattern. Whether orthodox or unorthodox approaches work better depends on the situation.