Noun. 1. lower mantle-the deeper part of the mantle. layer-a relatively thin sheetlike expanse or region lying over or under another. mantle-the layer of the earth between the crust and the core.1  Facebook.. lower mantle-the deeper part of the mantle. layer-a relatively thin sheetlike expanse or region lying over or under another. mantle-the layer of the earth between the crust and the core.
Constitutional amendment. A constitutional amendment refers to the modification of the constitution of a nation or state. In many jurisdictions the text of the constitution itself is altered; in others the text is not changed, but the amendments change its effect. The method of modification is typically written into the constitution itself.
The Amendment process is the formal way to change the Constitution. An amendment may be proposed by two-thirds vote of both houses of Congress or by a convention called by Congress at the request of two-thirds of the state legislatures.