|00:50Playing the banjo using the thumb, index and middle finger is loosely termed Three Finger Style. [This method was first used by "classical" banjoists in the late 1800's, who adopted the style from the guitar, and played on gut strings without picks. In the modern context ] Most people are referring to Scruggs style when they use this term.
Snuffy Jenkins is one three finger player who predates Scruggs. Don Reno, along with the single string style he is known for, played a three finger style that was, according to Tony Trischka, distinctly different. Among other things, his three finger work tended to use a lot more of the B string when playing rolls where others would use the G string. [Bluegrass three-finger-players use a thumb pick and finger picks to play.]