Ratification is the act of giving official sanction to a formal document such as a treaty or constitution. It includes the process of adopting an international treaty by the legislature, a constitution, or another nationally binding document (such as an amendment to a constitution) by the agreement of multiple sub-national entities. The process of ratifying a constitution is most commonly observed in federations such as the United States, confederations or international organisations sui generis such as the European Union. A good example would be George Read ratifying the United States Constitution.
In unionized workplaces, during negotiations, a contract proposal by an employer, that may be acceptable to the collective bargaining committee, will be brought back for ratification, or a vote by the general membership, before the union can either accept or decline such a contract proposal. A ratified proposal means a "Yes" vote and will form the basis for the new CBA (Collective Bargaining Agreement) for that workplace.
Different organizations have different rules for how a constitutional change is ratified. Federations usually require the support of both the federal government and a certain percentage of the subsidiary entities. Some ratification processes also require a supermajority within legislatures.
The ratification of international treaties follows the same rules as the passing of laws in most democracies. Important exceptions are the United Kingdom, where treaty making is still a royal prerogative exercised by Her Majesty's Government, and the United States, where treaty ratification must be advised and consented to by a two-thirds majority in the U.S. Senate. The Senate does not actually ratify treaties. Once the Senate has given its advice and consent to ratification, the President ratifies the treaty by signing an instrument of ratification. While the United States House of Representatives does not vote on it at all, the requirement for Senate advice and consent to ratification makes it considerably more difficult in the US than in other democracies to rally enough political support for international treaties.
The application of the treaty or legislation is not possible until it has been ratified, so we think. Usually this must be done first by both parties (in July 2006 British bankers contested their extradition to the US in application of a treaty not yet ratified in America), or in a multilateral agreement it may be provided that a quorum (e.g. half) of the signatories must have ratified it.

Ireland
The ratification of the current Contitución was achieved by plebiscite