Scintilla

A glimmer; a spark; the slightest particle or trace.

"Scintilla of evidence" is a metaphorical expression describing a very insignificant or trifling item of evidence. The common-law rule provides that if there is any evidence at all in a case, even a mere scintilla, that tends to support a material issue, the case cannot be taken from the jury but must be left to its decision.