Add quickstart to terms.md

Add quickstart and definition.

Author: Amanda Butler

docs/introduction/terms.md

@@ -24,7 +24,7 @@
 
 **BLE** - [Bluetooth Low Energy](/docs/v5.7/reference/ble.html).
 
-**Blinky** - An [example application](/docs/v5.7/tutorials/your-first-program.html) that you can use to get to know Arm Mbed OS and the development tools. It’s one of the simplest examples of Mbed OS.
+**Blinky** - An [example application](/docs/v5.7/tutorials/quickstart.html) that you can use to get to know Arm Mbed OS and the development tools. It’s one of the simplest examples of Mbed OS.
 
 **Block Device** - A [file](/docs/v5.7/reference/contributing-storage.html#block-devices) that represents a device, with data that can be read or written to it in blocks.
 
@@ -88,7 +88,7 @@
 
 ### L
 
-**Library** - A module you can use to build applications.
+**Library** - A module that you can use to build applications.
 
 **LoRA** - Long range (low power wireless platform).
 
@@ -114,6 +114,10 @@
 
 **Pull Request** - Used by version-controlled repositories to propose and collaborate on changes.
 
+### Q
+
+**Quickstart** - A getting started guide to Mbed OS.
+
 ### R
 
 **REST** - Representational State Transfer (API).