KPI
Etymology
An initialism for "key performance indicator," a phrase from late-twentieth-century management practice. "Key" signals selectivity — the few metrics that matter most — while "indicator" (from Latin "indicare," to point out) admits it merely points toward performance rather than being it. The abbreviation spread with corporate dashboards.
noun · /kay-pee-EYE/
A "key performance indicator" — a specific measure an organization tracks to judge how well it’s hitting a goal.
What it names
It forces the question "how would we actually know we’re succeeding?" and answers it with a number everyone watches.
Example
Customer response time became the team’s north-star KPI after complaints spiked.
Related idea
A metric is any measurement; a KPI is the small set of metrics you’ve chosen as decisive. Track too many "key" indicators and none of them is key. Beware Goodhart’s law: once a KPI becomes a target, people optimize the number rather than the thing it stood for.