Banjo refers to stringed plucked instruments. It resembles the standard mandolin typical for Europe, and this is not by chance, because banjo is its closest relative, even their sound is similar, except for the fact that the sound of the African "brother" is sharper and louder.
There are several stories about how ukulele got its name.
According to the most popular one, it is called a “jumping flea” in Hawaiian, because the player’s fingers moved as fast as that little bug. Another story attributes the ukulele name to Edward William Purvis, an Englishman and one of the officers in Hawaiian king David Kalakaua’s court, who had the same nickname because of his short stature and fidgety manner,