Before the Spaniards arrived to the peninsula, the area was called el Mayab by the Mayans meaning "a few." It was a very important region to the Mayans with many of their key cities.
After the Spanish conquest, the Yucatan Peninsula became a single administrative and political entity. The region was renamed Yucatan out of confusion. Before the Spaniards conquered the area, they had sent conquistadores for early exploration.
In 1517, the Spanish explorers were trying to communicate with the Mayans. They asked for the name of the region, but the Mayans couldn’t understand them.
They simply said something along the lines of “I don’t understand you” in their native tongue. It ended up sounding like “Yucatan” to the Spaniards, and they continued to call the area by that name.
The same thing happened in Australia and the aborigines. When the Europeans came to explore the land, they asked the native aborigines the name of an interesting animal that was very tall and hopped on its two back feet.
The aborigines said “kangaroo” which meant “I don’t understand you.” The Europeans thought they had given them the name of the animal and called it a kangaroo ever since.