The term PROPOSAL PROP can be broken down into two crossword solutions: KNEE (4 letters) and DIAMONDRING (11 letters). KNEE is a joint in the middle of the leg that connects the thigh and lower leg bones. It is also the most commonly used joint in the body for bending and straightening the leg. DIAMONDRING is a type of jewelry that is typically made with a diamond set in a metal band. It is a popular choice for engagement rings and other special occasions.