1. (n.) Lydian stone; basanite; -- so called because used to test the purity of gold and silver by the streak which is left upon the stone when it is rubbed by the metal. See Basanite.

2. (n.) Any test or criterion by which the qualities of a thing are tried.

acid test assay barometer benchmark blank determination brouillon canon check criterion crucial test crucible degree demonstration determination docimasy essay feeling out first draft gauge graduated scale kiteflying measure model norm ordeal parameter pattern probation proof quantity reading readout reference rough draft rough sketch rule scale sounding out standard test test case trial try type value verification yardstick