"Avocado is also known as the “alligator pear” because of the rough skin on some varieties. In the 17th and 18th centuries the fruit was also commonly known as “butter pear.” In tropical Central America, avocado trees have been growing wild for thousands of years... The Aztecs called the tree Ahuacatl. Marauding Spanish armies changed this to abocado or avocado, the now common English name.
According to the Little Green Avocado Book, there is strong evidence that avocado trees flourished 50 million years ago in what is now California, and avocados might have provided food for dinosaurs."