This is the 14106th most frequent Russian word.
олени
"Олени" in English means "deer."
In this sentence, "олени" is used as the plural form of "олень" (deer) to denote the plural object seen in the forest.
Я видел оленей в лесу.
I saw deer in the forest.
Here, the word "оленьи" is an adjective form derived from "олени" to describe the tracks belonging to deer.
Оленьи следы были видны на снегу.
Deer tracks were visible on the snow.
"олени" is used here as the plural form to describe a figurine depicting multiple deer.