The term "oolong tea" refers to a number of teas of intermediate oxidation. Unlike green tea, oolong tea is partially oxidized before steaming, baking, or frying. Unlike black tea, oolong tea is not fully oxidized; it remains at least partially "green". The less-oxidized oolongs are very similar in taste to green tea, while the highly oxidized oolongs of India's Darjeeling region are often mistaken for black tea.
For a more detailed treatment, see Tea.