I don't remember it being explained in the movies. Does the title have any meaning and where did it come from?
AFAIK, this is unexplained, even in the books. In the movies, the term is introduced in Goblet of Fire by Arthur Weasley when he confirms to Harry that they were attacked by Voldemort's supporters after the Quidditch World Cup, but the name's meaning is never touched upon.
According to a prevalent theory that could be found here on SF&F, the name is supposed to reflect Voldemort's own contempt for mere mortality and his desire to control and ultimately transcend Death, to be the thing that preys on Death and not the other way around - which is something he eventually set out to do by using Horcruxes. I don't believe Rowling ever supplied an explanation for the name.
This question has already been asked and answered on another site (one dedicated to all forms of science fiction and fantasy, books as well as films). The short version is that the name symbolises the aim of overcoming and defeating Death, which consumed much of Voldemort's life. From the accepted answer there:
Voldemort's followers were called "Death Eaters" because one of Voldemort's key goals was to use magic to fully control Death, directing its powers at Voldemort's sole command. Voldemort sees this as the sign of ultimate power, which is his foremost goal; to be the most powerful sorcerer ever.
Obviously, killing (directing Death toward others) is easy; it's preventing Death from turning on you that's tricky. The third leg of the triangle formed by the Hallows, recalling others from Death, was never of interest to Voldemort, and even the Resurrection Stone didn't really do that.
The name, therefore, arose from what being one of Voldemort's disciples means at a fundamental level. It means that you believe in Voldemort's philosophy, that mortality is a weakness of lesser beings, and that to become truly powerful, you must fear neither dealing death or succumbing to it; in the vernacular, you "eat Death for breakfast".