| Noun | 1. | mercury - a heavy silvery toxic univalent and bivalent metallic element; the only metal that is liquid at ordinary temperaturesmetal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc. cinnabar - a heavy reddish mineral consisting of mercuric sulfide; the chief source of mercury | |
| 2. | Mercury - (Roman mythology) messenger of Jupiter and god of commerce; counterpart of Greek Hermes | |
| 3. | Mercury - the smallest planet and the nearest to the suninferior planet - any of the planets whose orbit lies inside the earth's orbit solar system - the sun with the celestial bodies that revolve around it in its gravitational field | |
| 4. | mercury - temperature measured by a mercury thermometer; "the mercury was falling rapidly"temperature - the degree of hotness or coldness of a body or environment (corresponding to its molecular activity) | |