Tertullian UK /tɜːˈtʌli.ən/US /təɹˈtʌli.ən/ adjective1 •Of, relating to, or in the style or manner of Quintus Septimius Florens Tertullianus from Carthage.And so the Malay C.P.O. listened, with a Tertullian willingness to believe, to the white men's stories. — 1959