What is the term for a wedge-shaped burial container that is broader at the shoulders?

The term for a wedge-shaped burial container that is broader at the shoulders is "coffin." Traditionally, coffins are designed with a tapered shape, which reflects their wider dimensions at the shoulders and a narrower end at the feet. This design is intended to accommodate the human form, providing a more aesthetically pleasing and functional way to present the deceased.

Coffins can be made from various materials and are often used in burial ceremonies. The distinctive shape is what sets it apart from caskets, which typically have a rectangular shape and are designed with the intention of a more uniform appearance. Thus, the broader outline at the shoulders specifically aligns with the characteristics of a coffin, making it the correct answer for the question.