Homologation is a technical term, derived from the Greek homologos for "agree," which is generally used in English to signify the granting of approval by an official authority. This may be a court of law, a government department, or a professional body, any of which would normally work from a set of strict rules or standards to determine whether such approval should be given. The word may be considered very roughly synonymous with accreditation, and in fact in French may be used with regard to academic degrees. Certified is another possible synonym, while to homologate is the infinitive form.
In today's marketplace, for instance, products must often be homologated by some public agency to assure that they meet standards for such things as safety and environmental impact. A court action may also sometimes be homologated by a judicial authority before it can proceed, and the term has a precise legal meaning in the law codes of some countries.
In the project of the European Union, the word is used in those papers that are direct translations from French to refer to the processes of making trade standards and laws consistent throughout the whole of the union. British journalists usually prefer to use the term harmonisation for this purpose.
Another usage pertains to the biological sciences, where it may describe the similarities used to assign organisms to the same family or taxon, similarities they have jointly inherited from a common ancestor.
Perhaps the closest this word comes to everyday usage is in reference to racing vehicles. Many motorsports fans know that a vehicle must be homologated by the sanctioning body in order to race in a given league, such as NASCAR or Formula One. The names of the Ferrari 250 GTO and its namesake, the Pontiac GTO, preserve this sense of the word, as the initials stand for "Gran Turismo Omologato," the Italian for "Grand Touring, Homologated."