The etymology of the word "stacker" traces back to the noun and verb "stack", which itself originates from a Scandinavian source related to Old Norse stakkr meaning "haystack" or "heap". The root is Proto-Germanic stakon- meaning "a stake," and ultimately from the Proto-Indo-European root steg- meaning "pole" or "stick".

Stacker as a noun is formed by adding the agentive suffix -er to the verb stack, meaning "one who stacks" or "a device that stacks". The earliest known use of the noun "stacker" dates to the mid-1700s, while the verb form "stacker" has origins in Middle English, with evidence from before 1300, and is borrowed from early Scandinavian languages.

In modern usage, stacker can refer to: -Any person or thing that stacks items, such as a worker stacking shelves or a machine stacking bulk materials like coal or ores. -A device or machine used for piling bulk materials into stockpiles, often found in industrial contexts. -Informally, a person who collects precious metals in small forms like coins or bars.