Hourglass

Part of speech: noun

Pronunciation: /ˈaʊəɡlɑːs/

Definitions

1. A device with two glass chambers connected by a narrow passage, containing sand that flows from the upper chamber to the lower one to measure the passage of time
2. A time-measuring instrument consisting of two connected glass bulbs with sand flowing between them at a controlled rate
3. An ornamental or functional apparatus featuring two glass spheres linked by a constricted opening through which granulated material descends to indicate temporal duration

Etymology: A compound so literal it is almost a description: "hour" plus "glass," the glass being the transparent vessel that holds the sand. The device works by letting sand run from one bulb into another through a narrow neck, so each measured interval is simply the time the sand takes to fall. Before mechanical clocks became common, this was one of the few portable ways to time a fixed span, and its name points straight at the mechanism. The word "hour" comes into English from Old French "hore," which traces back through Latin "hora" and Greek "hōra," originally meaning a season or a fixed time of day. "Glass" is a native English word, so the compound mixes a borrowed term for time with a Germanic material word. Together they describe the object exactly, with no metaphor needed.

Synonyms: sand timer, timer, timepiece