What do we call a change to the Constitution?

A change to the Constitution is referred to as an amendment. The process of amending the Constitution is established to allow for changes over time, reflecting the evolving values and needs of society. An amendment can be proposed by either a two-thirds majority in both the House of Representatives and the Senate or by a constitutional convention called for by two-thirds of the state legislatures. Once proposed, an amendment must be ratified by three-fourths of the state legislatures or conventions to become part of the Constitution.

The term "revision" typically implies a broader overhaul or a complete rewriting of a document rather than the specific addition or change signified by an amendment. A "clause" refers to a distinct section or provision within a legal document but does not denote a change to that document. "A declaration" generally refers to a formal statement or announcement and is not used within the context of constitutional changes. Thus, the term that best describes a formal change to the Constitution is indeed an amendment.