What title does the son of a lord have in A Song of Ice and Fire?

Question

I don't fully understand the system of titles in the ASOIAF series - referring to the books or the series equally - in terms of lords. Catelyn corrects a gaoler who uses the title "Lord" for Edmure Tully while Hoster Tully is alive in A Clash of Kings (bold emphasis mine):

"Begging your forgiveness, m'lady, but Lord Edmure says no one is to see the Kingslayer without a writing from him, with his seal upon it."

"Lord Edmure? Has my father died, and no one told me?" ...

"You will open the cell, or you will come with me to Lord Hoster's solar..."

So, from this I understand that Edmure Tully isn't actually a Lord until Hoster Tully, Lord of Riverrun, dies. But what is Edmure's title? He wasn't knighted as far as I remember, so does he have any title at all while his father lives, as the first-born male? And while I understand that (spoilers for GOT) ...

Robb Stark automatically becomes the Lord of Winterfell when Lord Eddard Stark dies (until he styles himself "King in the North"

... what about Bran and Rickon Stark? Do they have any titles, before or after this event? I seem to remember Maester Luwin addressing Bran as "my prince", but I may have imagined this, and if not may just be a term of affection than a tiele.

So basically I have two questions:

1) What title is given (if any) to the first-born male child of a Lord?

2) What title is given (if any) to any other children of a Lord?

Answers from the books or series are acceptable. Be sensitive of spoilers, of course.

Answer 1

As with most things in ASoIaF, we're never given any clear explanation for their system of assigning titles -- the Westeros rules of peerage. We've seen this same issue pop up on this site many times, including Why is Cersei commonly referred to as "Cersei Lannister" instead of "Cersei Baratheon"? or Can a Bastard, under any circumstance, become a Lord or King in Game of Thrones. As with those other questions, since Martin seems to cleave pretty closely to medieval England for Westerosi society, we can make some very educated guesses.

In general, any member of a noble family would, upon reaching the age of majority, be entitled to be called Lord or Lady Whomever. Until the age of majority, boys would be called Master Whomever (e.g. Master Rickon or Master Tommon), which I believe we have seen in the novels as well. Underaged girls would usually get the honorific Lady anyway, as the direct counterpart to "Master" is "Miss", which isn't quite as formal.

The primary difference between the head of a House and his sons is that the actual Lord of a House, say Ned Stark, would be identified as any of the following, starting with the most formal: Lord of Winterfell, Lord Stark, Lord Eddard Stark, Lord Eddard. His son, however, is not entitled to either of the first two titles, only the last: Lord Robb Stark, or Lord Robb, so long as his father is alive.

There is, however, a key exception to this rule, and it's the one that Edmure Tully falls into. Namely, he's been knighted. From what I can tell, in the Westerosi rules of peerage, the title of "Lord Tully" would take precedence over the title "Ser Edmure", which in turn would take precedence over the simple title of "Lord Edmure". Thus, as long as Hoster Tully lives, his son is Ser Edmure, but upon Hoster's death, he would become Lord Edmure. That appears to be what Catelyn was chastising the gaoler about.

---

As far as the comment about Brandon being a "prince", which I'm pretty sure was made at least once in the novels, that title would have been valid at any point after Robb declaring himself King in the North. As soon as the Stark's household and lesser sworn houses recognize Robb as their King, his brothers and sisters would immediately become Prince and Princess Whatever, as they would now be in line to inherit Robb's throne upon his death.

Answer 2

In the fist season there is a scene with Theon Greyjoy and Osha:

Theon: In civilized lands, you refer to your betters by their proper titles.
Osha: And what's that?
Theon: Lord.
Osha: Why?
Theon: Why? What do you mean why? My father is Balon Greyjoy, Lord of the Iron Islands.
Osha: What's that got to do with you? If your father's lord, how can you be lord too?
Theon: I will be lord after my father ...
Osha: so you're not lord now?
Theon: No, you ... Are you having a go at me? Is that it?

From that I think that officially son becomes a Lord after his father's death. That would support what @Michael Edenfield wrote.

Answer 3

I think they could call him "Sir" when he's old enough. I remeber a chapter of Catelyn, when she call someone "Sir" but they said that the title is honorific because he didn't have any land.

Answer 4

Maybe "lordling"? Waymar Royce is called a lordling in the prologue to A Game of Thrones. He is the third son of Lord Yohn Royce, Lord of Runestone.

Here is the relevant paragraph (context: Gared is advising Ser Waymar Royce to return to Castle Black):

The lordling seemed not to hear him. He studied the deepening twilight in that half-bored, half-distracted way he had. Will had ridden with the knight long enough to understand that it was best not to interrupt him when he looked like that. "Tell me again what you saw, Will. All the details. Leave nothing out."

(page 3 of the Bantam books edition).

Note that in this paragraph, it's not entirely clear whether it's the objective voice of the author calling Ser Waymar "a lordling", or whether it's Will's inner monologue.