Mining farm is the established term for a facility that runs many mining machines with dedicated power, cooling and maintenance. The plural farms suggests more than one site, a portfolio of locations or a provider that operates farms for others. German mining circles use the English term as well, so the name needs no translation. The .de ending anchors it in Germany, where energy sourcing and heat reuse are central questions for miners.
bitcoinfarms.de belongs to the Bitcoin Mining DACH set, which covers hashrate, hashpower, pools, farms and nodes. Typical projects are a mining company running several sites, a hosting provider placing customers' machines in managed halls, a platform selling mining contracts to private investors, or an engineering firm building containerised farms powered by surplus energy.