Beef up definitions of sprints and agile | PM handbook

src/content/docs/pm-handbook/guide/agile-sprints-profusion-of-terms.mdx

@@ -10,15 +10,25 @@ Our team uses an **agile** **Sprint** workflow in **Jira** and **GitHub** to man
 
 ## Agile [#agile]
 
-Rather than define agile from scratch, here's an excerpt [from Wikipedia](https://en.wikipedia.org/wiki/Agile_software_development):
+People use agile to mean everything from a specific system of work (which we call sprints), to just "moving fast, preferably in a way that lets me bend things to my whims." 
+
+Luckily, we don't need to define it from scratch. Wikipedia does [an admirable job defining it](https://en.wikipedia.org/wiki/Agile_software_development):
 
 > Agile software development is an approach to software development under which requirements and solutions evolve through the collaborative effort of self-organizing and cross-functional teams and their customer(s)/end user(s). It advocates adaptive planning, evolutionary development, empirical knowledge, and continual improvement, and it encourages rapid and flexible response to change.
 
 For our team, that means our process is optimized to ship early and often. This lets us respond swiftly to changes in the product roadmap. More importantly, it ensures we validate our solutions with stakeholders, and that we're not letting valuable work sit around and get moldy when it could be out in the world making our users' lives better.
 
-## Sprint [#sprint]
+## Sprint (AKA scrum) [#sprint]
+
+This is the particular flavor of agile we follow. The sprint system (often referred to as scrum) is one major approach to Agile, along with other Agile systems such as Kanban. Sprint systems are often accompanied by a lot of jargon and best practices, but for our team the most essential elements are:
+
+* Working in strict timeboxes (two weeks in our case)
+* Planning that sprint in advance, and not changing the scope of the sprint (much) once it starts
+* Expecting all team members to contribute to making the sprint a success
+
+The video [Agile Product Ownership in a Nutshell](https://www.youtube.com/watch?v=502ILHjX9EE) (18 minutes) is an excellent resource for learning about Agile methodology. The Kindle book [Scrum: a Breathtakingly Brief and Agile Introduction](https://www.amazon.com/Scrum-Breathtakingly-Brief-Agile-Introduction-ebook/dp/B007P5N8D4/) is also a great read that you can get through in a short afternoon. 
 
-This is the particular flavor of agile we follow. Sprint is one major approach to Agile, along with other Agile systems such as Kanban. The video [Agile Product Ownership in a Nutshell](https://www.youtube.com/watch?v=502ILHjX9EE) (18 minutes) is an excellent resource for learning about Agile methodology. The Kindle book [Scrum: a Breathtakingly Brief and Agile Introduction](https://www.amazon.com/Scrum-Breathtakingly-Brief-Agile-Introduction-ebook/dp/B007P5N8D4/) is also a great read that you can get through in a short afternoon. For more on the "why" of Sprint as our chosen methodology, see the section [Agile for our team](3379_INSERT_LINK_HERE). And for more on the "how," see [Sprint workflow](3379_INSERT_LINK_HERE).
+For more on the "why" of Sprint as our chosen methodology, see the section [Agile for our team](3379_INSERT_LINK_HERE). And for more on the "how," see [Sprint workflow](3379_INSERT_LINK_HERE).
 
 ## Jira and GitHub projects [#jira-and-github-projects]