adv 1  :  by means of sight  :  with or to the eye <as viewed >   2  :  with reference to or by means of optics  :  with reference to optical properties <vitamins measured >  < ground surfaces>  .
 
 
 
Similar sounding terms:  op·ti·cal 
 
Published under license with Merriam-Webster, Incorporated.  © 1997-2024.