This is the 869th most frequent Russian word.
авиации
"Авиации" means "aviation" in English, referring to the design, development, production, and operation of aircraft.
The word "авиации" is used in its genitive singular form to indicate possession or association with aviation.
История авиации начинается с первых полетов.
The history of aviation begins with the first flights.
Here "авиации" stands for the genitive singular case, denoting the training center related to aviation.
Она работает в учебном центре авиации.
She works in an aviation training center.
In this sentence, "авиации" is used in genitive singular, showing the association of development with the concept of aviation.