"Blend of Terri and Ann"
The name Terriann is commonly a female name from the "English" origin.
Terriann is a modern American compound name made from two familiar English elements: Terri, a short form of Teresa, and Ann, a form of Anne. Names of this pattern, two common given names joined without a hyphen, appear frequently in twentieth-century United States records, and Terriann itself first shows up there in 1945. The name does not carry a meaning of its own beyond the two parts it is built from.
The pronunciation of Terriann is TEHR-ee-an.