certification UK /ˌsɜː.tɪ.fɪˈkeɪ.ʃən/US /ˌsɝ.tɪ.fɪˈkeɪ.ʃən/ noun3 •The act of certifying. •The granting of a certificate. •A professional qualification that certifies a person's ability.You do not possess the certifications required for this post. formscertifications