It has come to mean anyone who contracts with the federal government for benefits.
Before the 14th Amendment was ratified, the nation only had one class of Citizen -- spelled with a capital "C", who were subject to the jurisidiction of their individual states and not the federal government.
It's no big secret anymore, for practically everyone has traded their free status "Citizenship" in to the federal government and are now referred to as citizens, lower case "c". Check it out. The U.S. Constitution did not mention 'citizen' until the 14th Amendment -- and since then all amendments have used the word spelled with a lower case 'c'.
Sorry, but it's really that simple. And yes, Virginia, there are two classes of people in America. Congress couldn't use the word 'Citizen' to apply to the free slaves, for it was already defined in the Constitution as a white person. So they went for second best and used the lower case spelling for the free slaves, (and any one else who applied for bennies) which denoted federal jurisdiction.
"It's no big secret anymore, for practically everyone has traded their free status "Citizenship" in to the federal government and are now referred to as citizens, lower case "c". Check it out. The U.S. Constitution did not mention 'citizen' until the 14th Amendment -- and since then all amendments have used the word spelled with a lower case 'c'."
The capital 'C' versus lower case 'c' distinction is irrelevant. All, or virtually all nouns were capitalized in the COTUS. It was the style. It has gone out of style since and it is now considered proper only for proper nouns.