Meaning of the word heartland in English

What does heartland mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

heartland

US /ˈhɑːrt.lænd/
UK /ˈhɑːt.lænd/

Noun

the central or most important part of a country, area, or field of activity.

Example:
wildlife sites in the heartland of Russia