Wiktionary
mandocello
n. A string instrument similar to a mandolin.
Wikipedia
Mandocello
The mandocello is a plucked string instrument of the mandolin family. It has eight strings in four paired courses, tuned in fifths like a mandolin, but is larger, and tuned CC-GG-dd-aa (low to high in pitch). It can be described as being to the mandolin what the cello is to the violin.