Definition of "hourglass"

hourglass

/ˈaʊəɡlɑːs/

noun
plural hourglasses
1. A clock made of two glass vessels connected by a narrow passage through which sand flows.
  Quotations
  The sands of thy short life are spent this hour, / And no hand in the universe can turn / Thy hourglass, if these gummed leaves be burnt / Ere thou canst mount up these immortal steps.
  1819, John Keats, “Canto I”, in The Fall of Hyperion
2. (graphical user interface) A cursor, often shaped like an hourglass, indicating that the computer is busy.
  Quotations
  When I right click the desktop display to check Display Properties, it hangs and shows me only the hourglass instead of the display menu.
  2002, Maximum PC (Winter 2002, page 16)