It might be worth mentioning the concept of "stub resolver" and clarifying a bit that a nameserver is a resolver. That might be being pedantic, but thought it might be worth clarifying that the difference conceptually may just be what the particular dns server answering the query is authoritative for, if anything.

One other thing that might be worth a mention is the concept of the OS' resolver and "suffix search order", with an example of connecting (https, ping, ssh, whatever protocol) to a host using just the hostname, and the aforementioned mechanism that (probably) allows this to connect to the FQDN you want. (Also, now that I type that, do you mention "FQDN" at all? If not, maybe should.)

On that note one final thought that occurs to me is the error/confound that may occur if a hostname is entered and is not resolved, but does resolve with one of the domain suffixes attached on a retry (particularly can be confusing with a typo coupled with a wildcard A record in a domain, for example.) I recognize that the lines that look like DNS records are not explicitly stated to be in a format for any particular dns server software, and even if they were, they're snippets without larger context so we don't know what the $ORIGIN for the zone might be, an adjacent concept you might want to explore, even if just for your own edification is that of the effect of a terminating "." at the end of a hostname, either at resolution or configuration time.

Just offering feedback that might help you add to the article.