bellwether (n.)

• ancestor
• announcer
• antecedent
• avant-garde
• buccinator
• bushwhacker
• choirmaster
• choragus
• conductor
• doyen
• duce
• ewe
• explorer
• forebear
• forerunner
• frontiersman
• fugleman
• groundbreaker
• guide
• harbinger
• herald
• innovator
• lamb
• lambkin
• lead
• leader
• messenger
• messiah
• mutton
• pacemaker
• pacesetter
• pathfinder
• pilot
• pioneer
• point
• precedent
• precentor
• precursor
• predecessor
• ram
• ringleader
• scout
• sheep
• standard-bearer
• teg
• torchbearer
• trailblazer
• tup
• vanguard
• wether