"Blend of Gabri- and Anna"
The name Gabrianna is commonly a female name.
Gabrianna is a modern American formation, first appearing in US birth records in 1991. It joins the Gabri- element of Gabrielle and Gabriella to Anna, or equivalently to the -anna ending also seen in Brianna and Julianna. The compound is not a traditional name in any documented language.
The pronunciation of Gabrianna is gab-ree-AN-uh.