저녁 and 밤 저녁 is more like around dinner time 밤 is more like after late dinner time There is no specific period to distinguish between those But for me , 6pm- 8pm is 저녁 9pm -12pm is 밤

Hi, you probably mean 저녁. You are right! 저녁 typically refers to around dinner time (which is also evening), while 밤 refers to any time you should be asleep (aka night). Hope that helped!