I'm an American so I don't understand some of these British titles and whatnot. What "is" Grantham in the context of the story? Is it like a county?
In the UK there is a town called Grantham, but it's in Lincolnshire, not Yorkshire. It's also a surname apparently, but I'm not sure how common it is.
I think the main reason it was chosen for the character of Robert Crawley because it was a real title but no one holds it today. I could be wrong, though.
So when they say "Lord Grantham" is it like saying "Lord of Grantham" ? I know they don't say it that way, but just so that it makes sense. We don't have royal titles in the US, so when we hear something like "Lord Grantham," it sounds as if Grantham is his surname. Lord Grantham sounds to our ear like, say, President Obama. We put a title before a surname only.
No, that's just the formal way of addressing someone who holds a title, by using Lord and/or Lady, then referencing the title. Robert and Cora are the Earl and Countess of Grantham so instead of saying Mr or Mrs Crawley, they would be addressed as Lord and Lady Grantham. Then (for at least the men, as I haven't seen an example of this used for a woman on the show yet), there is a semi formal/informal addressing by using the first name and then referencing the title as if using Lord/Lady instead of the surname - Dickie Merton (surname Grey), Daniel Sinderby (surname Aldridge), and Tony Gillingham (surname Foyle, which he had used before he inherited the title).
For the children of those who hold titles, the sons of earls and all the children of barons and viscounts are referred to as Honourables - ex. The Honourable Larry Grey, son of Lord Merton. The daughters of earls, marquesses, and dukes are referred to as Lady (like Mary, Edith, and Sybil), while the sons of marquesses and dukes are called Lord. And those are the times where full names are used, because the children do not hold the titles yet.
Commoners of course are referred to as Mr/Mrs/Miss. Now, all of Robert and Cora's grandchildren thus far are referred to as such (though in George's case he is called Master George) because all of their fathers were commoners who did not hold titles.
Grantham is basically the name of the area of land (county or whatever) that went with the Earldom when first created. The real Earldom of Grantham existed in relation to an area of Lincolnshire but the title became extinct in 1754. This is why it is used in the show, so as not to upset any living people with the title.
Regarding surname, any landed aristocrat will adopt his title as his last name. So Robert would sign his name as simply "Grantham" and Cora as "Cora Grantham" or Violet as "Violet Grantham" even though their family name is Crawley. You see this today with Prince William who is known as William Wales in the RAF because he is a Prince of Wales (which is superior to his other titles).
As others have said, "Lord" is the form of address for all ranks of nobility from Baron to Marquess (Dukes are not called Lord, as it is the highest title before royalty, so they are addressed as Duke or my Lord Duke). So we have Lord Grantham (Earl of Grantham), Lord Flintshire (Marquess of Flintshire), Lord Sinderby (Baron Sinderby) but Duke Crowborough in an early episode.
The surname Grantham was adapted to the Surname Graham when the Lords went off to Scotland. :) Just FYI :)
What do you think?