The River Thames is the second longest river in the United Kingdom, but undoubtedly it is the most famous one because it flows through the heart of London.
The name Thames derives from the Brittonic Celtic name of the river, Tamesas. The original meaning of the name Thames is unclear, but it may have meant "dark" or "muddied".
The pronunciation of Thames is often confusing for foreign speakers because it is counter-intuitive. There are two rules to keep in mind. First, the "Th" is not pronounced as it would usually be in English, like in the word "thought". Instead, the "Th" is pronounced simply with a "T" sound. Second, the "a" is pronounced as if it were an "e", like in the word "dress".
Therefore, as heard in the audio pronunciation, the correct way to pronounce Thames in English can be phonetically written as Tems.