The Thai word for canal, and commonly used in English to refer to the canals of Thailand. The city of Bangkok is built on the delta of the Chao Phraya (q.v. for more information) and has been called the Venice of the East for its network of klongs connecting tributaries.
In recent years there has been an increase in public transport using the klongs, as was formerly traditional.
Used attributively: klong houses, klong cats, klong ferries, and so on. For pictures see
http://www.webprofessor.org/travels/asia/thailand/part_2.htm