pacemaker (n.)a leading instance in its field;
Synonyms: pacesetter
pacemaker (n.)a specialized bit of heart tissue that controls the heartbeat;
Synonyms: cardiac pacemaker / sinoatrial node / SA node
pacemaker (n.)an implanted electronic device that takes over the function of the natural cardiac pacemaker;
Synonyms: artificial pacemaker
pacemaker (n.)a horse used to set the pace in racing;
Synonyms: pacer /
pacesetter )window.location='https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=byronic106@yahoo.com&lc=US&item_name=Donation+to +Help+Keep+Etymonline+Free+and+Open&no_note=0&cn=&curency_code=USD&bn=PP-DonationsBF:btn_donateCC_LG.gif:NonHosted'){kind=link}