physics a measure of the extent to which a substance transmits light or other electromagnetic radiation, equal to the logarithm to base ten of the reciprocal of the transmittanceSymbol: τ Former name: optical density
No Offense, These Words Used To Be InoffensiveMake your mother proud . . . steer clear of these words that used to be inoffensive but can now do more harm than good.
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012