Term Kind Topic What it is
Latency metric Latency How long one operation takes — a distribution, never a number, and dominated by its tail in any system with fan-out.
Latency Budget Decomposition practice Latency Allocating a total response-time target across the components of a request path, so each layer has an explicit share and overruns are attributable.
Percentile Latency metric Latency Latency expressed as the value below which a given proportion of requests fall, used because averages conceal the behaviour that users notice.