A whale was a large aquatic animal.
On Earth, whales communicated though a collection of sounds known as whale song. (Star Trek IV: The Voyage Home)
A sperm whale's intestines created a concretion known as ambergris that was once used to stabilize the scent of perfumes. (TAS: "The Ambergris Element")
In 2286 an alien Whale Probe visited Earth attempting to reestablish communications with the previously extinct humpback whale species. (Star Trek IV: The Voyage Home)
A whale was also a main element in the Earth novel Moby Dick, the prey for Captain Ahab. (Star Trek: First Contact)
Types of whales