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.
History US Government. An amendment is a change or addition to the Constitution. The first 10 amendments to the United States Constitution are called the Bill of Rights. The Bill of Rights was ratified in 1791, only a short time after the Constitution was first ratified.