The name Isidore is a boy's name of Greek origin meaning "gift of Isis". Isidore and is often added to lists like Unique Boy Names: Unusual and Rare and discussed in our forums with posts like "Which would you choose?".
From the experts:
Isabel and Isadora are back: could it now be time for a more widespread revival of Isidore? In 2014, both Isidore and Isadore were on the list of fastest-rising names in the US.
A common ancient Greek name belonging to several saints--including Saint Isidore the Ploughman, patron saint of Madrid and the great encyclopedist St. Isidore of Seville, whose work formed the basis of much medieval knowledge--Isidore was adopted by Spanish Jews to the point where it was almost their exclusive property.
In addition to the obvious Izzy, another traditional nickname is Dore/Dory.