TOPIC: Iteration review vs iteration restrospective

So, I came across the term iteration (sprint) review and got to know that it's not as same as iteration retrospective.

It appears that:

 An iteration (or sprint) review is a meeting where the project team demonstrates the product increment that has been built during the iteration in order to get feedback from stakeholders and gain the approval of the product owner. The iteration review is not a meeting that is focused on process improvement.

And

Iteration Retrospective is a regular meeting where Agile Team members discuss the results of the Iteration, review their practices, and identify ways to improve.

Can someone please help confirm if my understanding is correct?

Thanks!

Yes that is correct.

At which ceremony does Customer give feedback and sign-off on the deliverable?

"Sign off" is not a Agile term per se, but during the SPRINT REVIEW you are demoing the latest build/functionality/features to the stakeholder/product owner. Based on this, the customer may say keep going, or I want to change direction, or I just thought of a new idea! All of these inform the stories in the backlog, which we will then reprioritize, add to, update, etc to get the next block of stories to be in the next sprint.