Add glossary for typically misused terms

README.md

@@ -9,6 +9,7 @@ The OpenTelemetry specification describes the cross-language requirements and ex
 ## Table of Contents
 
 - [Overview](specification/overview.md)
+- [Glossary](specification/glossary.md)
 - [Library Guidelines](specification/library-guidelines.md)
   - [Package/Library Layout](specification/library-layout.md)
   - [Concurrency and Thread-Safety](specification/concurrency.md)

specification/glossary.md

@@ -0,0 +1,50 @@
+# Glossary
+
+Below are a list of some OpenTelemetry specific terms that are used across this
+specification.
+
+## (Telemetry) Library
+
+Denotes the library that implements the *OpenTelemetry API*.
+
+See [Library resource semantic conventions](data-resource-semantic-conventions.md#library)
+
+<a name="instrumented_library"></a>
+
+## Instrumented Library
+
+Denotes the library for which the telemetry signals (traces, metrics, logs) are gathered.
+
+The calls to the OpenTelemetry API can be done either by the Instrumented Library itself,
+or by another [Instrumenting Library](#instrumenting_library).
+
+Example: `org.mongodb.client`.
+
+<a name="instrumenting_library"></a>
+
+## Instrumenting Library
+
+Denotes the library that provides the instrumentation for a given [Instrumented Library](#instrumented_library).
+*Instrumented Library* and *Instrumenting Library* may be the same library
+if it has built-in OpenTelemetry instrumentation.
+
+Example: `io.opentelemetry.contrib.mongodb`.
+
+Synonyms: *Instrumentation Library*, *Integration*.
+
+<a name="name"></a>
+
+## Tracer Name / Meter Name
+
+This refers to the `name` and (optional) `version` arguments specified when
+creating a new `Tracer` or `Meter` (see [Obtaining a Tracer](api-tracing.md#obtaining-a-tracer)/[Obtaining a Meter](api-metrics-user.md#obtaining-a-meter)). It identifies the [Instrumenting Library](#instrumenting_library).
+
+## Namespace
+
+This term applies to [Metric names](api-metrics-user.md#metric-names) only. The namespace is used to disambiguate identical metric
+names used in different [instrumenting libraries](#instrumenting_library). The [Name](#name) provided
+for creating a `Meter` serves as its namespace in addition to the primary semantics
+described [here](#name).
+
+The `version` argument is not relevant here and will not be included in
+the resulting namespace string.