What is the definition of certification?

Certification is the process through which an organization grants recognition to an individual, organization, process, service, or product that meets certain established criteria. For certification of individuals, the individuals usually have to meet eligibility requirements (such as education or years of experience), pass an examination, and pay a fee. There are also usually ongoing requirements that need to be met, such as retesting or participating in a minimum number of continuing education activities. Certification is voluntary - unlike licensure which is mandatory in order to practice in the licensed role in a given state. However, that's not to say it's not valuable - because some employers require or prefer applicants who are certified.
"certification" means that a state of affairs has been stated to be so, by means, most commonly, of a document self described as a certificate