What are these parts of hutch called?

[Chrispick77]

Hi all I'm fixing my daughters rabbit hutch and building a new lid,I've got some board and some felt but have no idea about the edges. What are the edges called so I can see about buying some of it. It has a groove inside to take the board,about 18mm.

 

[Stormer1940]

Smaller version of these I assume http://www.caldersdirect.com/garden-fen ... er-capping or http://www.caldersdirect.com/rebated-weather-capping