This is the 9990th most frequent Russian word.
апельсинового
"Of orange" (adjective, relating to the fruit or color).
Here 'апельсинового' describes the type of juice, indicating it is made from oranges.
Я выпил стакан апельсинового сока.
I drank a glass of orange juice.
In this context, 'апельсинового' specifies the flavor of the ice cream, derived from oranges.
Мы купили коробку апельсинового мороженого.
We bought a box of orange ice cream.
The word 'апельсинового' here defines the relation of the tree to oranges, suggesting it is an orange tree or related to oranges.