That's a really nice mnemonic. I wish I lived in an alternate universe where Postgres was called PostgreSQL so that it was easier to remember. Perhaps if we start using that, it will take over, like how everyone calls the Go project Golang.
(At least that's how I remember it as I was "why name a language like that when you know it won't be searchable")
My point is that almost everyone refers to it as Postgres, because they do not actually value the descriptiveness of "PostgreSQL".
Also because the original name was, just, "Postgres". Stylized as POSTGRES.
PostgreSQL is an awful neologism (OK it's been around for a while now), and I honestly thought that they had decided to switch back to the original, and clearly superior, name. :) I recall it being under discussion several years back, and I am surprised it did not happen.