* Hydro: This prefix comes from Greek and means "water".
* Meter: This suffix indicates a device or process for measuring something.
Therefore, a "hydrometer" is a device used to measure the specific gravity or density of liquids, usually water or other liquids containing water.
Here are some other possible meanings of "hydro" and "meter" combinations:
* Hydrometer: A device that measures water flow (e.g., a water meter).
* Hydro-meter: A device that measures the pressure or depth of water (e.g., a hydrostatic pressure gauge).
It's important to consider the context in which you encounter the word to determine the most accurate definition.