A constitution is classified as unwritten when it is not contained in any single document. This means that an unwritten constitution is not codified in a single written document, unlike a written constitution, which is a document that sets out the fundamental principles and rules by which a country is governed. An unwritten constitution, on the other hand, is based on a combination of sources such as custom, tradition, and judicial precedent. It evolves over time and is not limited by the constraints of a written document. Countries like the United Kingdom, New Zealand, and Israel have unwritten constitutions. In an unwritten constitution, the fundamental principles and rules of governance are not contained in a single document but are dispersed across various sources, and as such, they may be subject to interpretation and change over time.