This is the 271st most frequent Russian word.
многие
"Многие" means "many" or "many people."
In this sentence, 'многие' functions as an adjective modifying the plural noun 'люди', meaning 'many'. It quantifies 'люди', indicating a large but indefinite number of people.
Многие люди любят путешествовать.
Many people like to travel.
Here, 'многие' acts as a noun referring to many individuals. In the context, it suggests a general group of people who share a common action.
В последние годы многие начали интересоваться здоровым образом жизни.
In recent years, many have started to take an interest in a healthy lifestyle.
In this example, 'многие' is used as a pronoun standing for 'many individuals'. It's used to replace the understood group of people that offered help.