I was rereading LoC, and in Chapter 6: Threads Woven of Shadow, Graendal, Sammael and Semirhage all make references to a "binding".

 

I can't for the life of me remember what it refers to or if it's even particularly relevant to the story.

 

What are they talking about?

As far as I remember...they are talking about how the Aes Sedai bind themselves with the oath rod (binder), which was used on criminals in the AoL.

 

*I may be wrong

Yup...they are referring that AS use the Oath Rod (a binder as mentioned above) to enforce Oaths.  This is ironic as these were used to punish channelers in the Age of Legends.  If you'll recall they offered Semi this choice when they discovered she tortured her patients "To be bound never to know her pleasures again and see the end of her life approaching"