1. what do the words “good night” denote in these lines from dylan thomas' poem, "do not go gentle into that good night"?

Throughout the poem the speaker is pleading for his father not to die. He tells him to "rage, rage against the dying of the light." In the line "do not go gentle into that good night", the speaker is asking for his father not to die. The words "good night" refer to the end of life - death and eventually heaven.