A recess cut into in one or both sides of a log or other piece of timber, enabling several such pieces to be slotted together; a joint made using such recesses (occasionally in conjunction with a ridge or tenon).
Origin
Early 20th century.
Definition of saddle notch in US English:
saddle notch
noun
Woodworking
A recess cut into in one or both sides of a log or other piece of timber, enabling several such pieces to be slotted together; a joint made using such recesses (occasionally in conjunction with a ridge or tenon).