This is the 2242nd most frequent Russian word.
жилой
Suitable or intended for living (residential).
"Жилой" is used as an adjective describing the word "использование" to indicate that the use is residential.
Этот дом предназначен для жилого использования.
This house is intended for residential use.
"Жилые" is used as an adjective describing "кварталы" to indicate that these districts are intended for living.
В городе строят новые жилые кварталы.
New residential districts are being built in the city.
"Жилом" modifies "здании" describing it as a building for living or housing.