If you’re new to the observability space, it’s easy to get lost in a sea of terms. What are APMs, traces, spans, telemetry, and metrics? Are Jaeger and Zipkin actual words? What’s the difference between OpenTelemetry and OpenTracing? Let’s try to make sense of all this language. Let me present a complete dictionary of observability and distributed tracing terminology. Telemetry refers to the collection of signals that your applications, services, and infrastructure send to observability backends.