Mantle -

The area of the Earth that lies between the crust and the core. It is divided into two parts, the lower mantle is solid and about 2200km thick. The upper mantle is a viscous (molten) layer about 670km thick, it is solid at it's uppermost point just below the crust. See. lithosphere

Over meanings of this word can be found in the Longman: Dictionary of Environmental science. Click here to buy this book at a low price and with free P&P in the UK: