A male turkey is often called a "tom" turkey, because tom is used to refer to the male of many animal species. Calling a male animal a "tom" is most often used when referring to turkeys and cats.
It is rumored that Benjamin Franklin was the one who began to call male turkeys "toms." Benjamin Franklin thought that the turkey should be America's national bird instead of the bald eagle. Since Thomas Jefferson did not make the turkey America's national bird, Benjamin Franklin called turkeys "tom" after Thomas Jefferson. However, there is no proof that male turkeys were even called this during Franklin's and Jefferson's lifetimes, explains Barry Popik.