1. A device for measuring time, consisting of two glass chambers connected by a narrow neck through which sand falls: An hourglass can contain a certain quantity mercury, or another flowing substance besides sand, that trickles from the upper chamber to the lower in a fixed amount of time, often one hour.
2. A computer cursor that shows that a task is being performed, but is not yet completed: A laptop icon that looks like an hourglass is useful in indicating that it, the laptop, is still occupied with or engaged in some activity..

The shape of a human body that looks like a sand timer: Jill had an hourglass figure of a lady that was very narrow at her waist and quite wide at her hips and bust.