pilón
trough
pila
basin, sink
+
-ón
augmentative suffix
Pilón means trough and can be thought of as pila0 (basin or sink0) + -ón1 (augmentative suffix1), indicating a large basin or container for water or feed.
noun
- troughA large stone or concrete basin used for holding waterLos caballos beben agua del pilón. // The horses drink water from the trough.