The Amazon river runs through the Amazon... I'm not sure if the land area got the name from the river or the other way around. I see some mention of the company

The Amazon river runs through the Amazon... I'm not sure if the land area got the name from the river or the other way around. I see some mention of the company name referring to the river, but I wasn't sure if that was apocryphal, and I always associated the river and land together as part of the same thing. I could be wrong, in which case the company is named after a river, and shares the name with a jungle.