Joe, in the world of gun description, acronym and shorthand and terms particular to firearms abound.
SLE - sidelock ejector
SLNE - sidelock non-ejector
BLE - boxlock ejector
BLNE - boxlock non-ejector
All hammer guns I have seen are sidelocks; i.e., A type of action on a break-open gun where the lockwork (hammer, sear, mainspring etc.) is mounted to the back side (inside) of a plate (or pair of plates for a double gun).
Other actions would be boxlock or trigger plate, and
www.hallowellco.com has the best description of these terms in the "Firearms Dictionary" on its site.
Regards, Tim