After posting a review of the Craftsman Cordless Sabre Saw, I received the following question:
In recent years, the two terms are almost interchangeable, and up to the manufacturer. In the case of the cordless sabre saw linked above, one could just as easily argue that this tool is a jigsaw.
Years ago, what is now called a scroll saw (a tabletop model where the blade is fastened at both ends) was often referred to as a jigsaw, while the model with the blade affixed on one side would be referred to a scroll saw. As this latter, portable model became more popular, some manufacturers placed a knob on top of the unit that could be used to turn the reciprocating blade. As these models evolved, these were often referred to as a sabre saw, while similar models without the turning knob were called a jigsaw.
Another use of the term sabre saw is for the recipro saw, or reciprocating saw. These saws are available from a number of manufacturers, but are commonly referred to as a "Sawzall," the trademarked term for this type of sabre saw manufactured by the Milwaukee Electric Tool Company. This type of sabre saw is most often used in demolition and construction, but has little use in fine woodworking.
In the common nomenclature, the term jigsaw and sabre saw are, in most cases, interchangeable.
Research jigsaw saw reviews on Consumer Search.