(From mathematical jargon) An expression used ironically to characterise unquantifiable behaviour that differs from expected or required behaviour. For example, suppose a newly created program came up with a correct full-screen display, and one publicly exclaimed: "It works!" Then, if the program dumped core on the first mouse click, one might add: "Well, for suitably small values of `works'."
Compare the characterisation of pi under for values of.
Wide-angle single lenses should never be used except on a suitably small plate, so that the above conditions hold.