Short answers, pulled from the story.
An urn is a vase often with a cover featuring a narrowed neck above a rounded body and a footed pedestal. Describing a vessel as an urn generally reflects its use rather than any particular shape or origin.
Pottery urns dating from about 7000 BC have been found at an early Jiahu site in China. A total of 32 burial urns were discovered there according to Hu Yaowu's 2005 analysis.
Sir Thomas Browne published Hydriotaphia or Urn Burial in 1658 after discovering a Bronze Age urn burial in Norfolk England. This work documented the history of urn burials during that period.
Knife urns placed on pedestals flanking dining-room sideboards emerged as an English innovation around late 1760s. These pieces transformed functional storage into high-style dining room features before fading from popularity within the following decade.
Biodegradable urns use human remains to grow trees and include eco-friendly materials such as recycled paper salt cellulose or other natural products capable of decomposing back into natural elements. Some biodegradable urns include seeds intended to grow into trees at the burial site.