Meaning and history
Tibby is a Scots and English diminutive traditionally used for Isabella, and sometimes for Theobald or other names beginning with a similar sound. Isabella is a medieval form of Elizabeth, from Hebrew Elisheva, usually interpreted as “my God is an oath.” When Tibby derives from Theobald, however, its Germanic elements mean “people” and “bold,” so the underlying meaning depends on the full name intended. Tibby has mostly remained an affectionate nickname, and reliably documented prominent independent bearers are uncommon.