Real Dictionary

mercury
uncountable noun: Mercury is a silver-coloured liquid metal that is used especially in thermometers and barometers.

mercury in American English
the messenger of the gods, god of commerce, manual skill, eloquence, cleverness, travel, and thievery: identified with the Greek Hermes
noun: a heavy, silver-white, highly toxic metallic element, the only one that is liquid at room temperature; quicksilver: used in barometers, thermometers, pesticides, pharmaceutical preparations, reflecting surfaces of mirrors, and dental fillings, in certain

mercury in British English
noun: a heavy silvery-white toxic liquid metallic element occurring principally in cinnabar: used in thermometers, barometers, mercury-vapour lamps, and dental amalgams. Symbol: Hg; atomic no: 80; atomic wt: 200.59; valency: 1 or 2; relative density: 13.546; me

Mercury in British English 1
noun: the messenger of the gods

Mercury in British English 2
noun: the smallest planet and the nearest to the sun. Mean distance from sun: 57.9 million km; period of revolution around sun: 88 days; period of axial rotation: 59 days; diameter and mass: 38 and 5.4 per cent that of earth respectively