Ask HN: Epics, Themes, Initiatives, Features, Stories. Clear Articulation Needed

There seems to be so much written online. Unfortunately in a lot of publications, a lot of the terms are synonymous/interchangeable and/or open to interpretation.

Agile has it's roots in Software Development but is seeping more and more into other disciplines. Entire organisations are now going Agile.

However, most people have wild and varying understanding of the these terms.

How would you ELI5 the relationships/hierarchies between Epics, Themes, Initiatives, Features, Stories, Tasks, etc. and do you have any templates that you recommend to ensure people have the same understanding?