"Blend of Terri and Anna"
The name Terrianna is commonly a female name from the "American" origin.
Terrianna is a modern American formation built from two established given names: Terri, long used in the United States as a short form of Teresa, and Anna, a name with a continuous history in English and other European languages. Its first appearance in United States birth records in 1991 fits a twentieth-century coinage of this kind rather than an inherited name from a particular language. The name carries no meaning apart from whatever is attributed to its two parts.
The pronunciation of Terrianna is teh-ree-AN-uh.