Bert is a hypocoristic form of a number of various Germanic male given names, such as Robert, Albert, Elbert, Herbert, Hilbert, Hubert, Gilbert, Wilbert, Filbert, Norbert, Osbert, Bertram, Berthold, Bertrand, Umberto, Humbert, Cuthbert, Delbert, Dagobert, Rimbert, Egbert, Siegbert, Gualbert, Gerbert, Lambert, Engelbert, Friedbert, Gombert, Calbert, Leebert and Colbert. Wikipedia