Della is of Italian origin, derived from the word 'della,' meaning 'of.' It has been used as a given name since the 19th century and gained popularity in English-speaking countries during the mid-20th century. Della was popularized by characters in literature, such as Della Street, the secretary in Erle Stanley Gardner's Perry Mason novels.
"The name Della experienced varying popularity throughout the early 20th century, with peaks in the late 1920s and a notable high of 12 births in 1924."