Spatial memory safety is a reasonably common term in the security / PL field. You can see examples of it being used at least as far back as 2009: https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=spa...
It's in contrast to temporal memory safety, which deals with object lifetimes (use after free, for example).
Here Google is probably also referencing a 2022 post of theirs with a very similar title, dealing with temporal safety: https://security.googleblog.com/2022/05/retrofitting-tempora...
The terms are also in Wikipedia: https://en.wikipedia.org/wiki/Memory_safety#Classification_o...