What does the mc or mac in names like McDonalds mean?

Question:Does it heave a meaning, a purpose, what is it and why keep it?

Best Answer - Chosen by Asker: Does it heave a meaning, a purpose, what is it and why keep it?

Mac or Mc are generally understood to mean "son of". Many surnames have prefixes like this that mean "son of" - there is Fitz, for example - Fitzgerald means son of Gerald. MacHenry means son of Henry. McKay means son of Kay... and so forth. This does not happen only in English. In Arabic, the prefix Ibn also means "son of".
In the Nordic or Scandinavian languages, it comes at the end, in the form of sen or son, like Anderson, or Johanssen.

It is very interesting how the various surnames evolved. there is much more to know than the little you see here.

I hope this helps.

McDonalds is more than likely the maker's last name and its irish. there is many irish last names with Mc or Mac

Mac is a Celtic patronymic originally meaning "son of". It denotes a family or clan and variants are Mc and Mag ( e.g. Maginnis ).

It means "son," as in the English "Johnson," "Harrison," etc. Lots of family names come from names of fathers made into surnames. The older Norman families kept the "Fitz" surname, which also means "son." "Mac" is Gaelic and O is Irish.
Why keep it? Well, I suppose people are generally quite attached to their names and don't want their kids to change them. So in a way I suppose the old "son of" prefixes and suffixes still serve their original purpose (for the males at least).

both Mc and Mac have the say meaning which is son of So McDonald would be son of Donald.

The prefix Mac, Mc and Fitz means son of

The prefix O means descendant of.

Just to add a few more to the patronymic list....
<name> = person's name <father>=father's name

Hebrew.... <name > ben <father>(son of).... <name> bet <father>(daughter of)
Sweden.... <name> <father>npoika (son)....<name> <father>ntytar (daughter)
Dutch...<name> <father>zoon (son)...<name> <father>dochter (daughter)
Russian area.... <name> <father>vich (son) <name> <father>yvena (daughter)