Gilbert Look up Gilbert at Dictionary.com
male proper name, from O.Fr. Guillebert (from O.H.G. Williberht, lit. "a bright will") or O.Fr. Gilebert, from Gisilbert, lit. "a bright pledge," from O.H.G. gisil "pledge," a Celtic loan-word (cf. O.Ir. giall "pledge") + beorht "bright." It was the common name for a male cat (especially in short form Gib) from c.1450 (see Tom).