When I earned my M.A. at the University of Texas at Austin in 1995, the M.A. was the option for coursework and original research in the form of a thesis. The M.S. was reserved for the coursework-only option (rarely awarded).
In 1996 (I believe), the department changed the thesis-based Master's to an M.S. degree and did away with any no-thesis degrees higher than Bachelor's. This decision short-sells the awardee, unfortunately.
In general, an M.S. in STEM fields indicates a coursework-only degree (typically 6 classes, no thesis or original research) and an M.A. indicates a more rigorous course of study and research.
My Master's thesis, btw, is "Desorption of High Explosives from Soil: Thermodynamics and the Role of Soil Organic Carbon."
I did not know that. Thanks for the explanation!
The essence of my answer is based on the way things were in my graduate programs at my university when I was in school there; and some observations from so-called terminal Master's degree programs.
In my doctoral program in chemistry, the M.S. was "awarded" to Ph.D. candidates who did not pass orals and was referred to as "the booby prize." Having been admitted to candidacy and completing my doctorate, I have only a Ph.D. in chemistry and not a Master's of any kind.
Having said all that, almost every M.S. I've seen during interviews over the past 20 years has been a terminal degree lacking a thesis - but I am a scientist, and I see mostly physics/chemistry/geology/mathematics resumes and not engineering or CS ones.
Few would argue that a BA in physics (which would actually be in Natural Sciences) from Cambridge is "less rigorous"
¹ There's a fee...
² https://en.m.wikipedia.org/wiki/Master_of_Arts_(Oxford,_Camb...
Generally speaking, though it varies by state, Engineer in Training after passing the Fundamentals of Engineering exam, then you must work under a Professional Engineer (PE) for $x years and pass the PE exam to officially call yourself an engineer.
For the PG (Professional Geologist):
https://tbpg.state.tx.us/licensing/p-g-licensure/p-g-licensi...
and, for the GIT (geoscientist-in-training):
https://tbpg.state.tx.us/licensing/geoscientist-in-training-...
In my case, I took and passed the Fundamentals of Geology (ASBOG) exam in 2014 (and have at least a Bachelor's degree AND a minimum of 30 hours of geosciences coursework). I've held and renewed (continuing education) my license (GIT-98) yearly.
What has stopped me from getting my PG is that I haven't accumulated enough time working in the geosciences since earning my degree almost 30 years ago!
But I very much would like to, and that's a different story.
Obviously can't speak for parent's case (and I recognize geography is not geology), who has provided a very nice answer, but I wanted to just throw out there that sometimes it's all kind of... nebulous.