This is the 14th most frequent Russian word.
году
"Году" is the dative or prepositional case form of "год" (year), meaning "in the year" or "to the year" depending on context.
Году here is in the prepositional case to indicate a time point.
В 2020 году я путешествовал по Европе.
In 2020, I traveled across Europe.
Году here is in the dative case to match with the preposition каждому.
Каждому году свой характер.
Each year has its own characteristics.
Года here is in the genitive case to express the type or kind of year with the adjective такого.