The Golden Smoothee apple is a smooth russet-resistant sport of the Golden Delicious apple.
A "sport" is a naturally occurring anomaly on a fruit tree that differs from the tree's main variety. They happen regularly in nature, and when desirable sports are noticed by farmers and/or horticulturists, they are often propagated to form new cultivars.
"Though I am old with wandering
Through hollow lands and hilly lands, I will find out where she has gone
And kiss her lips and take her hands; And walk among long dappled grass,
And pluck till time and times are done, the silver apples of the moon
The golden apples of the sun."