An apple tree is an angiosperm whose seeds are enclosed within its fruit.

angiosperm 由希腊词根 angio-（意为"容器、包裹"）和 sperm（意为"种子"）组成，字面意思是"种子被包裹的植物"，即"被子植物"，这类植物的种子被果实包裹保护。