The small streams and springs at the source of a river, where the river begins high in mountains or hills.
From Old English 'heafod' (head) and 'wæter' (water). The compound emerged in the 1600s as geography-focused language developed, using 'head' metaphorically for the source or origin point of flowing water.
The Amazon's headwaters are so remote and pristine that scientists are still discovering new species there—the beginning of a river's journey often holds more secrets than its famous mouth!
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