The kumquat is a citrus fruit. Unlike other citrus fruits, the skin of the kumquat is edible, although the seeds are not. The skin and fruit are sour and sweet, respectively.
There are four major varieties of kumquat, often spelled "cumquat" in some English-speaking countries. These include the Hong Kong wild, the Marumi, the Meiwa and the Nagami, with the latter two varieties most often grown in the United States. The word "kumquat" comes from the Cantonese words for "golden orange." Horticulturists presume these fruits to be native to China. Kumquats tend to be small fruits and grow on shrubs or small trees.