The word gerbil is a diminutive form of  jerboa , though the jerboas are an unrelated group of rodents occupying a similar ecological niche.
A variance is a form of equitable relief that allows a property owner to bypass local zoning laws so they can use their land in the most efficient manner possible. When unusual circumstances make it difficult for a property owner to comply with local zoning laws, cities and counties may grant what are known as variances to allow property owners to circumvent the traditional zoning laws in an area.
A variance is a waiver of a setback requirement or height restriction in the code. It allows the owner to build closer to the property line than the code allows. For example, in an R-1 single family single and duplex zoning district, the minimum setback requirement for the rear is 10 feet on each side.