bactericidal,a.Biol.|bækˈtɪərɪˌsaɪdəl| [f. bacteri-um + L. -cīda slayer + -al1.] Destructive to bacteria. 1878Tyndall in 19th Cent. Mar. 506 The bactericidal effects which his theory ascribes to pressure.1881― Float, M. Air 48 All bactericidal media are therefore anti-septic.