You're describing a pension. I'm gathering from the comments that this isn't a globally recognised term, but it's like a flat (or inflation-linked) post-retire

You're describing a pension. I'm gathering from the comments that this isn't a globally recognised term, but it's like a flat (or inflation-linked) post-retirement salary based on how much you've paid into it over the years. If you don't get to a pensionable age, you get nothing. Longer you live after that threshold, the more you get paid.