Apple has a very loyal customer base because Apple products are very well made.
Of course, the word "apple" is very common in English. You probably knew it already. But are you familiar with these expressions?:
The apple doesn’t fall very far from the tree. (A child is very similar to a parent.)
She (or he) is the apple of his eye. (A parent is very proud of his son or daughter.)
It’s like comparing apples to oranges. (You’ll hear this said when someone tries to make a comparison between two extremely different things. This may invalidate the comparison.)
An apple a day keeps the doctor away. (This is a common proverb in English. Eating apples keeps a person healthy, so there’s no need for a doctor.)
Note: Apples are often used to represent teachers and the teaching profession. Why is that? There are a few reasons. First, I think it’s because students often give their teachers apples as gifts. Giving your teacher an apple is a way to express your appreciation for the work that the teacher does. Second, apples are not very expensive and can be eaten anywhere. Overworked teachers don’t have a lot of time (or money!) for lunch, so they eat apples.