If there's a movement towards "node" to refer to the database which has the Subscription object, then perhaps the documentation for
31.2. Subscription, Chapter 31. Logical Replication should be updated as well, since it uses both the "database" and "node" terms on the same page, and to me referring to the same thing (I could be missing a subtlety).
See:
"The subscriber database..."
"A subscriber node may..."
Also, the word "database" in this sentence: "A subscription defines the connection to another database" to me works, but I think using "node" there could be more consistent if it’s referring to the server instance running the database that holds the PUBLICATION. The connection string information example later on the page shows "host" and "dbname" configured in the CONNECTION value for the SUBSCRIPTION. This sentence seems like the use of "database" in casual style to mean the "server instance" (or "node").
Also, the "The node where a subscription is defined". That one actually feels to me like "The database where a subscription is defined", but then that contradicts what I just said, and "node" is fine here but I think "node" should be on the preceding sentence too.
Anyway, hopefully these examples show “node” and “database” are mixed and perhaps others agree using one consistently might help the goals of the docs.
Thanks!