I. pace‧mak‧er /ˈpeɪsˌmeɪkə $ -ər/ noun [countable]

1. a small machine that is placed inside someone’s chest in order to help their heart beat regularly

2. (also pacesetter) a person or horse who goes to the front in a race and sets the speed that the others must try to achieve

[TahlilGaran] Dictionary of Contemporary English ▲

II. pace‧set‧ter /ˈpeɪs-setə $ -ər/ (also pacemaker) noun [countable]

1. a person or team that is winning in a competition, and that others have to try to defeat:
That left him three strokes behind the pacesetter, Parry.

2. a person or company that is considered to be a leader in a particular area of activity:
a new company, now seen as the industry’s pacesetter

3. pacemaker(2)

[TahlilGaran] Dictionary of Contemporary English ▲