This is the 147th most frequent Russian word.
разных
"Of different" or "various."
Here, 'разных' modifies 'fields', denoting a variety across subject areas.
Ученики изучают темы разной сложности и из разных областей.
Students study topics of varying complexity and from different fields.
In this example, 'разных' emphasizes the diversity and variety of 'directions' of ideas.
Мы обсуждали идеи различных направлений.
We discussed ideas of various directions.
In this sentence, 'разных' is used as an adjective meaning 'different' to describe the noun 'countries', indicating diversity.