1. The stiffening of the muscles that occurs several hours after someone dies: The medical examiner noted the degree of cadaveric rigidity or rigor mortis that was present as part of the estimation of the time of the victim's death.
2. The hardening of the muscular tissues of the body, from one to seven hours after death as a result of the coagulation of the myosinogen and paramyosinogen: The cadaveric rigidity disappears after one to five or six days, or when decomposition begins.

Sometimes the rigor mortis, or cadaveric rigidity in the corpse, makes it difficult to fit the body into the coffin for burial.

3. The postmortem stiffening of the voluntary and involuntary muscles of the body present a board-like situation for the entire body: The development of cadaveric rigidity may be poor or incomplete in elderly, very young, or severely debilitated individuals.