set ‧ ter /ˈsetə $ -ər/ BrE AmE noun [countable]
1 . a long-haired dog often trained to help hunters find where animals or birds are
2 . style-setter/trend-setter/standard-setter etc
someone who does things that other people admire and try to copy:
Liz has always been a fashion-setter.
3 . exam-setter/policy-setter etc British English someone who decides or organizes something as part of a job:
Who’s the question-setter for the quiz night?
⇨ set the pattern/tone/trend at ↑ set 1 (5), ⇨ ↑ pacesetter , ↑ trendsetter