You may be correct, but I'm not sure that even the senates can RE-define words that already have a definition. I think the Fourteenth Amendment establshed a precedent dis-allowing a re-defining of a word that was already defined in the U.S. Constitution.
I submit:
The word, 'Citizen,' (upper case 'C") in the constitution had a specific definition and Congress decided it didn't have the authority to change the definition of that word to include people that couldn't meet the qualifications demanded by that definition.
So it did the next best thing. It created another word, 'citizen,' (lower case) and an entirely new institution for those citizens, (federal citizenship) and bestowed upon this new group (or recognized) all the rights, privileges and protections heretofore enjoyed by 'Citizens.'
So rather than go through the Amendment process and create a new word that is similar to the word, 'marriage,' which is likewise legally defined, the Supreme Court in Mass. is in the process of re-defining the word to include a class or group of people that don't meet the qualifications demanded by the legal definition of that word..
Why didn't the supreme court of yesteryear do the same thing with the word, "Citizen," to include the freed slaves and other non-citizens whose rights were long over-due for recognition instead of going through the process of amending the Constitution?
I think it was because the supreme court knew it didn't have the right to change the definition of the word. If that be true (or even if was for a different legitimate reason), why does today's supreme court feel it has that right to subvert the amendment process?
Because they can, ergo might makes right, quod erat demonstrandum.