What is "white sapote"

Casimiroa edulis, with English common names casimiroa, white sapote, and Mexican apple, and known as cochitzapotl in the Nahuatl language (meaning '"sleep-sapote") is a species of tropical fruiting tree in the family Rutaceae, native to eastern Mexico and Central America south to Costa Rica. The genus is named for "an Otomi Indian, Casimiro Gómez, from the town of Cardonal in Hidalgo, Mexico, who fought and died in Mexico's war of independence."