A pallbearer is one of several funeral participants who helps carry the casket of a deceased person from a religious or memorial service or viewing either directly to a cemetery or mausoleum, or to and from the hearse which does so.
A pall is the heavy cloth that is draped over a coffin. Hence the metaphoric term "casting a pall" on a gathering of people, by announcing bad news to the group. By metonymy, the term "pallbearer" is used to signify someone who bears the coffin which the pall covers.
Some traditions distinguish between these two roles, with pallbearer being a ceremonial position, just carrying a tip of the pall or a cord attached to it, while casketbearers do the actual heavy lifting and carrying. There may otherwise be only pallbearers in the literal sense while the casket is on an animal or on an animal-drawn or motorized vehicle.
Pallbearers are usually associated in an intimate manner with the deceased before their death, though this is not always the case.