Scrabble?! PACEMAKER

Definitions of PACEMAKER in various dictionaries:

noun - a leading instance in its field

noun - a specialized bit of heart tissue that controls the heartbeat

noun - an implanted electronic device that takes over the function of the natural cardiac pacemaker

noun - a horse used to set the pace in racing

One who sets the pace in a race.

Also called pacesetter 3.

A part of the body, such as the mass of muscle fibers of the sinoatrial node, that sets the pace or rhythm of physiological activity.

Any of several usually miniaturized and surgically implanted electronic devices used to stimulate or regulate contractions of the heart muscle.

A substance that regulates a series of related reactions.