Cynda Lannister

 Cynda Lannister is a unseen character mentioned in the second season. Cynda is the mother of Ser Alton Lannister.

Background
Ser Alton's mother.

Season 2
In the Stark's stockade, Ser Alton say to Jaime, that he's mother is Cynda Lannister. But Jaime can't remember, therefore asking about she's the fat one. Ser Alton admits she's got a little rounder with the years, then Jaime says there only one fat Lanniser and he'll know it, if she was.

In the books
In the Song of Ice and Fire novels, there is no character named Cynda Lannister.