mantel-, mantle-, -manteau +

(Latin: mantellum, cloak, veil; by way of Middle English, from Old English mentel and from Old French mantel; resulting in English words about: mantle, mantel, and manteau)

mantle plumes
A pipe-shaped mass of heat-softened light rock which rises from the mantle toward the crust of the earth.
mantle rock, regolith
1. The layer of loose rock resting on bedrock, constituting the surface of most land.
2. The layer of disintegrated and decomposed rock fragments; including soil, just above the solid rock of the earth's crust.
mantle transition zone
A layer in the mantle between 400 to 700 kilometers across in which there is an increase in seismic velocity because of the phase changes of the minerals present to more closely-packed, denser forms.
mantle, mantles, mantling, mantled (verb forms)
1. To cover with or as if with a cloak and to conceal by extending over a surface: "The streets and cars were mantled in snow."
2. To become covered with a coating; such as, scum or froth on the surface of a liquid.
3. The spreading of their wings over food as is done by hawks.
mantlet, mantelet
1. A very short cape or cloak worn by women in the 19th century.
2. A mobile screen or shield or a portable bulletproof screen or shelter which was formerly used to protect besieging soldiers or soldiers attacking a fortress.
3. A protective military shield or armor, or similar protection; such as, that in front of a gun, or attached to the front of a tank.
portmanteau, portemanteau (s) (noun); portmanteaus, portmanteaux (pl)
1. A case or bag for carrying clothing and other necessaries when traveling; originally, of a form suitable for carrying on horseback; now applied to an oblong stiff leather case, which opens like a book, with hinges in the middle of the back: Leonard packed his portmanteau to carry on the train when he was traveling.
2. A combination of word parts to create a new word that is made up of the blended sounds of two other distinct words and combining the meanings of both of them: "Smog" and "motel" are examples of linguistic portmanteaus with "smog" meaning smoke + fog and "motel" meaning motor + hotel.
3. Etymology: from French porter, "carry" + manteau, "cloak, mantle".

See these additional examples of Portmanteau words.

whole-mantle convection
The theory that the entire mantle, of hot land soft rocks, circulates and mixes in the course of bringing heat from the outer core to the surface.