Generally referred to as coffins, in contemporary North American English there is a distinction made between coffins, which have six sides in cross-section, and caskets, which have four sides.

First attested in English 1380, the word coffin derives from the Old French "cofin", from Latin "cophinus", which is the romanization of the Greek "κόφινος" (kophinos), "basket". The earliest attested form of the word is the Mycenaean Greek ko-pi-na, written in Linear B syllabic script.

Any box used to bury the dead in is a coffin. Use of the word "casket" in this sense began as a euphemism introduced by the undertaker's trade in North America; a "casket" was originally a box for jewelry. North Americans may draw a distinction between "coffins" and "caskets", using coffin to refer to a tapered hexagonal or octagonal (also considered to be anthropoidal in shape) box used for a burial and casket to refer to a rectangular burial box with a split lid used for viewing the deceased as seen in the picture above. Receptacles for cremated and cremulated human ashes (sometimes called cremains in North America) are called urns.

A coffin may be buried in the ground directly, placed in a burial vault or cremated. Alternatively it may be interred above ground in a mausoleum, a chapel, a church, or in a loculus in catacombs. Some countries practise one form almost exclusively, whereas in others it may depend on the individual cemetery.

The handles and other ornaments (such as doves, stipple crosses, crucifix, symbols etc.) that go on the outside of a coffin are called fittings (sometimes called 'coffin furniture' - not to be confused with furniture that is coffin shaped) while organising the inside of the coffin with fabric of some kind is known as "trimming the coffin".

Cultures that practice burial have widely different styles of coffin. In some varieties of Orthodox Judaism, the coffin must be plain, made of wood and contain no metal parts or adornments. These coffins use wooden pegs instead of nails. In China and Japan, coffins made from the scented, decay-resistant wood of cypress, sugi, thuja and incense-cedar are in high demand.

Sometimes coffins are constructed to permanently display the corpse, as in the case of the glass-covered coffin of the Haraldskær Woman on display in the Church of Saint Nicolai in Vejle, Denmark or the glass-coffin of Vladimir Lenin which is in the Red Square in Moscow.

When a coffin is used to transport a deceased person, it can also be called a pall, a term that also refers to the cloth used to cover the coffin.

Coffins are traditionally made with six sides, tapered around the shoulders, or rectangular with four sides. Continental Europe has favoured the rectangular coffin or casket, although variations exist in size and shape. In Medieval Japan, round coffins were used,which resembled barrels in shape and were usually made by coopers. (In the 1961 Kurosawa film Yojimbo, the protagonist, anticipating a shortage of coffins due to an impending battle (planned by Yojimbo) persuades several coopers to start making more coffins.) In the case of a death at sea, there have been instances where trunks have been pressed into use as a coffin.

They may incorporate features that claim to protect the body or for public health. For example, some may offer a protective casket that uses a gasket to seal the casket shut after the coffin is closed for the final time. In England, it has long been law that a coffin for interment above ground should be sealed; this was traditionally implemented as a wooden outer coffin around a lead lining, around a third inner shell. There are occurrences of coffins lined with or constructed from lead to bury radioactive-contaminated dead. However, in practice, after some decades have passed, the lead may ripple and rip. In the United States, numerous states require a vault of some kind in order to bury the deceased. A burial vault serves as an outer enclosure for buried remains, the coffin serves as an inner enclosure.