This is the 16618th most frequent Russian word.
сельское
Rural.
The word 'сельское' here is used as an adjective modifying 'хозяйство', meaning 'agriculture', referring to rural activities related to farming.
Я люблю сельское хозяйство.
I love agriculture.
The word 'сельское' modifies 'местечко', meaning 'place', indicating that the location is situated in the countryside.
На выходные мы отправляемся в сельское местечко.
We are heading to a rural place for the weekend.
In this sentence, 'сельское' describes 'развитие', meaning 'development', referring to matters and progress pertaining to rural areas.