I have recently been educated by Dimcl that,
[Does this mean that an Oxford comma is exactly the same as a serial comma? - askoxford.com give two different definitions for the two terms.]Askoxford.com defines a serial comma as:
Serial comma (also Oxford comma) n. a comma used after the penultimate item in a list of three or more items, before 'and' or 'or' (e.g. an Italian painter, sculptor, and architect).
My question now is, what do you call the type of comma in the sentence examples below?
I want to discuss health and safety. [one concept]
I want to discuss health, and safety. [two concepts]
We should invite Wiremu and Mary. [W&M seen as a unit]
We should invite Wiremu, and Mary. [W&M seen as two separate units]