Order Robes and Peerage Cloaks
Order Robes
Once upon a time, the Order of the Laurel in Caid decided that they wanted to make Order Robes. This was researched, and resulted in the Order as a whole adopting Order Robes of a cloak in the Kingdom colors with the badge of the order on the left breast. See Complete Anachronist #115, "I See by Your Outfit" for more information about historical Order Robes.
The Order of the Pelican in Caid discussed having Order Robes, but eventually the discussion died, and so there is no Order Robe defined for the Order of the Pelican in Caid. However, the Laurels who are also Pelicans have used the Laurel style, with a Pelican badge. So there is, de facto if not de jure, an Order Robe for the Order of the Pelican in Caid.
What makes a blue cloak with white lining an Order Robe? The badge on the left breast. Otherwise, it is just a pretty cloak.
Peerage Robes
Historically, in Great Britain, the peerage (which includes Barons) have a specific set of Peerage Robes that are worn on great occasions. These are cloaks that have a prescribed number of bands of fur around the cloak. This author is not aware of any SCA usage of Peerage Robes.
Armorial Cloak
An armorial cloak is one which has the bearer's arms and armorial achievement upon in. Anyone who has a device registered with the SCA College of Arms is free to display it, including on a cloak. The most common places are the back of a cloak, or on the left breast of the front of a cloak.
Peerage Cloak
This appears to be an SCA- specific term for an armorial cloak with an achievement that indicates that the wearer is a peer.