An hourglass is a device that was used to measure the passing of an hour. It has two round glass sections linked by a narrow channel, and contains sand which takes an hour to flow from the top section into the lower one.
英汉词典释义
n.
沙漏
an hourglass figure沙漏形的图形an hourglass design沙漏状的图案Once the sands have run out of a person's hourglass, they cannot be replaced.时光一去不复返。