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.
An amendment to the Constitution is a change that can add to the Constitution or change an older part of it. An amendment can even overturn a previous amendment, as the 21st did to the 18th. There are a few methods to amend the Constitution, but the most common is to pass an amendment through the Congress, on a two-thirds vote. After that, the amendment goes to the states, and if three-quarters of the states pass the amendment, it is considered a part of the Constitution â it has been ratified.