IPA: /ˈpeɪsˌsɛtə/
KK: /ˈpeɪsˌsɛtər/
A person or thing that sets a standard or example for others to follow, especially in a competitive context.
The athlete was a pacesetter in the marathon, inspiring others to improve their times.
Pacesetter → It is formed from "pace" (from Old French *pas*, meaning step or pace) and "setter" (from the verb "set", meaning to place or establish). A pacesetter is someone who establishes a pace or standard for others to follow.
Think of someone who is 'setting' a 'pace' for others to follow — that's what a pacesetter does.