This is the 4594th most frequent Spanish word.
ballenas
"Ballenas" means "whales" in English.
In this sentence, 'ballenas' refers to the marine animals, whales, in a general context about their characteristics.
Las ballenas jorobadas son conocidas por sus cantos.
Humpback whales are known for their songs.
Here, 'ballena' specifies a single whale in the context of an exhibit.
En el museo, vimos un esqueleto de ballena impresionante.
At the museum, we saw an impressive whale skeleton.
In this case, 'ballenas' refers metaphorically to the supports used in clothing, derived from historical usage of whale bones.