[Jtsummers]

They're similar, lists of tasks/items to check off. However, when most people talk about checklists they're often talking about it in particular contexts and a more deliberate construct than todo lists. Pilots, for instance, have pre-flight checklists. This is not an ad hoc todo list (the more common sense of "todo list") with arbitrary and possibly unrelated tasks (go to grocery store, pick up dry cleaning, outline paper).

Checklists, especially in system operations and safety contexts, also tend to have a bit of a procedural characteristic, possibly including conditional and even looping constructs or sub-procedures.

  - If HPA is energized
    - [ ] De-energize HPA
  - [ ] Enter radome

And order is important to many, but not all, checklists in a way that's not as clear in todo lists. You can probably pick up the dry cleaning before the groceries, or on a separate errand run, for instance. If you don't de-energize the HPA, you're possibly setting yourself up for some pain and suffering if you enter the radome while the system is energized.