Chiroplast is an instrument to guide the hands and fingers of pupils in playing on the piano, invented by Johann Bernhard Logier. The instrument was a sliding wooden frame that placed the wrist, thumb and fingers of a hand above five consecutive white keys of a keyboard, to overcome the difficulty of retaining their proper position by beginners. I...
• (n.) An instrument to guid the hands and fingers of pupils in playing on the piano, etc.
Chi'ro·plast noun [ Greek ... formed by hand; 
A chiroplast is an instrument used to guide the hands and fingers of pupils in playing on the piano, etc.
cheiroplast, chiroplast An instrument to guid the hands and fingers of pupils in playing on the piano, etc.