Bellwether
Etymology
From Middle English: belle, “bell,” + wether, “a castrated ram.” Shepherds hung a bell on the ram that led the flock so its movements could be heard and the rest would follow. From “the sheep the flock follows” came “the case a trend follows.”
noun · /BEL-weth-er/
A leading indicator that signals which way a trend is about to move.
What it names
The early signal you watch to predict a larger shift — a single case whose behavior reliably foreshadows the whole group’s.
Example
That swing district is a bellwether; as it votes, the state has gone for decades.
Related idea
A bellwether predicts where things are heading; a touchstone tests how good something already is.
noun · /BEL-weth-er/
The lead sheep of a flock, which wears a bell so the shepherd can track the rest.
What it names
the belled ram the flock follows
Example
The other ewes trailed the bellwether across the field.
Related idea
From “bell” + “wether” (a castrated ram): because the flock follows it, the word came to mean a leading sign of where things are headed.