Kuala Lumpur means "muddy confluence" in Malay; ''Kuala'' is the point where two rivers join together or an estuary, and ''lumpur'' means "mud". One suggestion is that it was named after Sungai Lumpur ("muddy river"); it was recorded in the 1820s that Sungai Lumpur was the most important tin-producing settlement up the Klang River. Doubts however have been raised on such a derivation as Kuala Lumpur lies at the confluence of Gombak River and Klang River, therefore it should rightly be named Kuala Gombak as the point where one river joins a larger one or the sea is its ''kuala''. It has been argued by some that Sungai Lumpur in fact extended down to the confluence (therefore the point where it joined the Klang River would be Kuala Lumpur), although this Sungai Lumpur is said to be another river joining the Klang River  upstream from the Gombak confluence, or perhaps located to the north of the Batu Caves area.