A casket is generally a four-sided burial box, most commonly in use these days.
A coffin is the type of funerary box that has six sides to it. Think of what they used in old fashioned Victorian or Old West burials, and you get the idea.
This type is also called a "toe pincher," as the shape is narrower down toward where the feet would go.
My dear Hubby spends a good deal of time in his workshop during the warmer weather, creating all sorts of interesting wooden & metal items for Halloween. He whipped up a whole bunch of mini scale-sized (18" x 6" x 3") toe pincher coffins that we sold at "Monsters & Merriment." People used them to put candy in, or bottles of wine, dolls (they fit a regular sized "Barbie" perfectly) or autumn foliage displays.
They're all hand-made from repurposed wood (mostly pine and/or cedar) with metal hinges that he created from hand as well.
Each is unique, with characteristics of the wood they are created from. Some have big piney knotholes, including one with a heart-shaped knot hole on the lid. And one of the black ones has a hand-sculpted skull that he created, festooned on the lid.
We keep a few around the house year-round, and any time we have company over who have never been to our "Halloween 24/7/365" home, they always ask where we got those cool coffins from!
They are available on my Etsy store, for only $25 each plus shipping.
Our dear friend, the illustrious Nashville TV horror host "Dr. Gangrene," just featured one of the coffins on his YouTube channel giveaways a few days ago. You can see it here:
DR. GANGRENE'S THANKSGIVING GIVEAWAY