The inhumation bell is the big, corroded bell found in the tower of the Assassins' Guild in Ankh-Morpork, “inhumation” being the Guild’s preferred term for the service they provide. It is rung to toll the hour - though a little bit behind the correct time - but also to assemble the Guild Council (Men at Arms), to announce an assignment has been successfully completed by a Guild member, and when an old pupil of the Guild's school has died. (Discworld's Assassins' Guild Yearbook and Diary 2000, Turtle Recall, The Ultimate Discworld Companion)
- It’s function may be a reference to the Division Bell that is rung in or around the parliament of some Commonwealth countries to signal a division, calling all members of the affected chamber to vote. In the UK, members in the Commons or in the House of Lords have eight minutes once the bell is sounded to get to the appropriate Division Lobby and vote for or against the resolution. This certainly matches the description of the Guild Council scrambling to quickly attend Dr Cruces when he rings the Inhumation Bell after Vimes’ visit in Men at Arms.
- It may also be a reference to the Lutine Bell which hangs in the offices of famous maritime insurance agency Lloyds of London. This bell was traditionally struck when news of an overdue ship arrived - once for the loss of a ship (i.e. bad news), and twice for her return (i.e. good news). Pratchett never specifies how many times the Inhumation Bell is rung for its various uses.