A junk is a type of Chinese sailing ship with fully battened sails. There are two types of junk in China: Northern junk, which developed from Chinese river boats,: 20 and southern junk, which developed from Austronesian ship designs, which have been trading with the Eastern Han dynasty since the 2nd century AD.: 12–13 They continued to evolve in later dynasties, and were predominantly used by Chinese traders throughout Southeast Asia. They were found, and in lesser numbers are still found, throughout Southeast Asia and India, but primarily in China. Found more broadly today is a growing number of modern recreational junk-rigged sailboats. Chinese junks referred to many types of coastal or river ships. They were usually cargo ships, pleasure boats, or houseboats. Historically they have ranged in size from small river and coastal vessels to large ocean going ships, and there are significant regional variations in the type of rig, however they all employ fully battened sails.
The term "junk" (Portuguese junco; Dutch jonk; and Spanish junco) was also used in the colonial period to refer to any large to medium-sized ships of the Austronesian cultures in Island Southeast Asia, with or without the junk rig. Examples include the Indonesian and Malaysian jong, the Philippine karakoa and lanong, and the Maluku kora kora.