improve wording

Author: reyang

specification/metrics/sdk.md

@@ -708,12 +708,12 @@ A Push Metric Exporter MUST support the following functions:
 
 ##### Export(batch)
 
-Exports a batch of `Metrics`. Protocol exporters that will implement this
-function are typically expected to serialize and transmit the data to the
-destination.
+Exports a batch of [Metric points](./datamodel.md#metric-points). Protocol
+exporters that will implement this function are typically expected to serialize
+and transmit the data to the destination.
 
 The SDK MUST provide a way for the exporter to get the [Meter](./api.md#meter)
-information (e.g. name, version, etc.) associated with each `Metric`.
+information (e.g. name, version, etc.) associated with each `Metric point`.
 
 `Export` will never be called concurrently for the same exporter instance.
 `Export` can be called again only after the current call returns.
@@ -728,10 +728,10 @@ are being sent to.
 
 **Parameters:**
 
-`batch` - a batch of `Metric`s. The exact data type of the batch is language
-specific, typically it is some kind of list. The exact type of `Metric` is
-language specific, and is typically optimized for high performance. Here are
-some examples:
+`batch` - a batch of `Metric point`s. The exact data type of the batch is
+language specific, typically it is some kind of list. The exact type of `Metric
+point` is language specific, and is typically optimized for high performance.
+Here are some examples:
 
 ```text
        +--------+ +--------+     +--------+