I have aPhd in medical science and a BSc in biology an open mind and the ability to research and analytically read other research so feel reasonably qualified to comment and be critical of the medical profession. My GP agrees and has said "rhematologists know very little but spend all of they time trying to split auto immune diseases into ever more numerous categories but have no tools to treat them and little research into their causes" He is a highly intelligent well educated man and excellent doctor.
Syndrome means "we don't know but it's too complicated for us to work out" It is a term used to describe multiple symptoms which vary considerably between people but it doesn't fit the neat tick box method of defining disease created by "modern" western medicine. It is sadly used all to often to mean "it's not that serious nothing we can do but it won't kill you"
Phenomenon means nothing it an old fashioned term meaning something we see but don't know what causes it.
Actually Raynauds is a disease, allegedly may be primary or secondary, but it is not known what causes it other than it is assumed that vaso spasticity is the mechanism but what triggers the "incorrect " response is unknown.
The use of these terms should be deprecated as they trivialise very serious malfunctions of the body and have an organic if as yet unidentified cause.
Before microscopes we didn't know about bacteria and before electron microscopes we didn't know about viruses and many "diseases" were attributed to bad air, bad blood - use leeches, bad water or even evil spirits. There's no difference now and then, until knowledge progresses or medics have open minds then we will always face this - remember Lorenzo's oil!
I have met the 2 so called top Sjogren's specialists in the UK both rheumatologists and they don't know what they are doing, are completely out of date with research have closed minds and dismiss any ideas or new thoughts but have no suggestions as to causes or what happens as the disease progresses and even refuse to accept that neurological damage, cystitis, depression, panic attacks, postural hypotension, urethritis, arthralgia etc .. are caused by or even symptomatic of Sjogren's. The term "quack" springs to mind however they are very highly paid. I was told by one "you don't have Sjogren's you are sero negative and according to our international definitions you only have 3 out of 4 tick boxes so cannot have it - you have sicca syndrome, but even if you did have Sjogren's there's no treatment I can give - bye"
My wife has witnessed all of these conversations.
I don't see the point of fretting about terms other than they are used by the medical profession to trivialise illnesses they don't understand and hide their ignorance.
Dementia and Alzheimers aren't called sydromes or phenomena but no one knows what causes them however they are spending hundreds of millions of pounds researching them and even had a politician led international conference in UK about coming together globally to find a cure but spend nothing (in the UK and from what I can see in the USA) on Sjogrens research.