Sand glass, also known as an hourglass, is a popular time-keeping device that consists of two bulbs connected by a narrow neck and filled with sand that moves from one bulb to the other. While sand glass is the most common term used to refer to this device, there are several synonymous words that can be used to describe it. These include time glass, egg timer, sand clock, and sand timer. The word hourglass is also frequently used to describe this device, as it measures an hour of time. Synonyms for sand glass have been used for centuries, and they have become popular due to their practical use in measuring time and the aesthetic value they add to any interior decoration.