This is the 940th most frequent Bulgarian word.
населени
"Населени" means "populated."
Here, 'населени' is used as an adjective to describe places (места) that are inhabited by people.
Населените места в тази област са многобройни.
The populated areas in this region are numerous.
'Населена' is used as a past participle (passive form) denoting that the action of inhabiting by people occurred on the territory.
Тази територия е населена от хиляди години.
This territory has been inhabited for thousands of years.
Although not using 'населени' explicitly, 'население' stems from the same root and refers to the inhabitants or population.