Master's and bachelor's degrees--why the apostrophe s?

Factual Questions
21

[QUOTE=robby]
Yes.

For whatever reason, that’s a term that registered nurses seem to use. My wife is a nurse, and she uses that term all the time.

Of course, she (and other nurses) also pronounce “centimeter” as “SAHN-tuh-mee-ter.” I don’t know where nurses come up with this stuff.
[/QUOTE]

So does my father the retired doctor. Must be a medical thing.

22

[QUOTE=Spectre of Pithecanthropus]
So does my father the retired doctor. Must be a medical thing.
[/QUOTE]

I’ve never noticed this in any of the medical personnel (sometimes in training) that I know. Maybe it’s an American medical thing?