Unusual middle names. Any ideas of why?

[Kiltaglassan]

Two spinster aunts who both died in the 1990’s. One had a middle name of Hunter which happened to be her paternal grandmother’s surname. The other had a middle name of Scott which turned out to be the surname of her maternal grandmother. Helped immensely in tracking down my great and great great grandparents.

[Erato]

Middle names:  I have one named after a failed candidate for president, two named after clergymen/college presidents and one after a postmaster.

[nanny jan]

My 2xgt. aunt was given, as one of her names, the married surname of her aunt (who had married "well"). Perhaps the parents were hoping for a legacy for their little daughter;  sadly she died as an infant.

[gaffy]

I've also encountered several instances where a brother-in-law's surname has been incorporated as a child's middle name (no prior blood relationship in the family tree), and then passed down to a further generation.  The same also with the surname of a business partner.

So yes, from my family context (predominantly Scotland / Northern Ireland), surnames as middle names aren't as rare as hen's teeth.  A great many do link back to family ancestors.  But some occasionally don't.     

[Erato]

Come to think of it, I had a business partner's surname used, too.  Surnames used as middle names are common in my tree, especially in the Scottish and Yankee New Englander branches.

[antiquesam]

My maternal grandfather, uncle and myself all have Rennie Malcolm as middle names. Both seem to be surnames from earlier generations. My mother's family were based in Angus.
I have no idea why this happened but assumed it was something to do with these branches had money.

[Gone]

I've an ancestor who had 3 sons all with the same Christian name, one died in infancy but 2 survived. They had different mothers so their middle name was their mother's maiden name, it must have been confusing though.
Griff

[ThrelfallYorky]

I've spent ages trying to track down how "Whiteley" became used as a recurring middle name in my Isherwoods - not helped by some descendants have interpreted it as "Wiley" or "Wikely" - neither of which are accurate, if you see images of the earliest usages of the name!
But then, there's a whole lot of confusion concerning "Isherwoods" generally, so I ought not to be surprised.
Most of the middle names have been as suggested on here, carrying the mother's or grandparent's original surname down the generations. Very occasionally I've found "godparents" - one of which actually proved to be the real parent of the person concerned - and a couple of times, local ministers or vicars.

[IgorStrav]

My Great Aunt had the middle name Bruce.

None of my cousins, her direct descendants, knew why this was.

The joking rumour in the family is that it referred to the name of the milkman