From Hebrew, Beelzebub is literally translated "Lord of the Flies." Beelzebub was one of the 7 princes of Hell. In ancient texts, he is associated with Ba'al, a polytheistic god, so he is obviously a foil to the monotheistic Jewish God Yahweh.
Given that Golding wrote the novel during the horror of and destruction of World War II, the title is relevant and fitting: Europe was a hell on Earth. Throughout the novel there are many allusions to the nature of evil and Beelzebub.
Ironically, the title 'Lord of the Flies' was not the original title for this novel by William Golding - and was not even chosen by him to begin with! Golding's initial choice for a title was much more prosaic and ordinary. It was his publisher's reader who first suggested an alternative title, and Golding was then happy with the new one. The idea of a lord of flies is certainly very spectacular and the vivid and mysterious image conjures many questions in a potential buyer's mind. Certainly, the title help to cause a steady stream of potential buyers to the book shops. The image of 'lord' goes back before classical times in most cultures where there was a feudal element and the 'flies' has connotations of Beelzebub, decay and the devil.
In the book "The Lord of the Flies" the school boys are stranded on a desert island with no adults. They begin to fall away from civilization and one boy begins to form his own tribe of hunters. Jack and his group of boys deteriorate into a savage like state.
When they first capture a pig, they cut its head off and place it on a stake in the ground. Simon, a more spiritual deep thinking young boy sees the head and begins to communicate with it. Flies buzz around it. During his conversation with the head, it ells him that "he is the beast." This is an indication that the beast is within the boys.
The head of the beast, pig, with the flies buzzing around it symbolizes death and the withdrawal from civilized ways. Jack, the protagonist in the story in a way becomes the Lord of the Flies as he controls his tribe through violence and threats using the other bigger boys. The title is very fitting because murderof a boy becomes something as natural as being able to murder the pig for food.