The English word
HORDE comes from a Turkic source; compare Turkish
ordu, meaning a camp or an army. You can see the word as
orda in Russian, and
horda in Polish. The word "horde" originally referred to a nomadic tribe or wandering group of people. Over time, "horde" came to refer to any large gathering of people, especially wild or fierce people.
The English word "horde" is very often confused with "hoard," a word that can be used as a noun (meaning treasure, especially hidden treasure) and also as a verb (meaning to store up, to hide away for future use). The word "hoard" is Germanic in origin, unlike the Turkic "horde."
Just to make things more confusing, the phrase "Golden Horde" refers to a Mongolian khanate which ruled over most of Eastern Europe in the 13th century, covering a territory reaching from the Urals to the Danube as well as most of Siberia, and ranging south down to the Black Sea. Hence the Russian borrowing of this word, along with many other words of Mongolian and Turkic origin. You can read more about the Golden Horde at
Wikipedia. The use of the word "golden" in this phrase adds to the confusion with the English word "hoard," meaning "treasure."
The illustration below shows the Mongolian "horde" at the
Battle of Mohi in 1241. You can read more about the Mongolian invasion of Europe at
Wikipedia.