A certificate is an official document affirming some fact. For example, a birth certificate testifies to basic facts regarding a person's birth. A certificate may also certify that a person has received specific education or has passed a test.
In computing and especially computer security and cryptography, the word certificate generally refers to a digital identity certificate also known as a public key certificate.
A certificate, in addition to certifying that someone has passed a test or reached a specific standard of knowledge may also be the name of an actual award, for instance students in the Republic of Ireland sit the Junior Certificate and follow it with the Leaving Certificate, in higher education the National Certificate is soon to be replaced by the "Higher Certificate". Similarly other countries have awards, for instance, Australia the Higher School Certificate is often the examination taken on completion of secondary education.