This is the 1014th most frequent German word.
keller
"Basement" or "cellar."
Here, "Keller" refers to a room located underground, typically used for storage or as a basement.
Der Keller ist kühl und dunkel.
The basement is cool and dark.
In this context, "Keller" is used in a compound noun "Weinkeller", denoting a specialized type of underground room designated for storing wine.
Im Weinkeller lagern wir die besten Weinsorten.
In the wine cellar, we store the best types of wine.
Here, "Keller" (though historically an alternate spelling) would refer to "Kellner," which is an actual word for 'waiter' or 'server'; note the modern spelling adjustment.