what does ounce mean
noun. 1  a unit of weight equal to one sixteenth of a pound (avoirdupois); 1 ounce is equal to 437.5 grains or 28.349 grams.2  a unit of weight equal to one twelfth of a Troy or Apothecaries' pound; 1 ounce is equal to 480 grains or 31.103 grams. 3  short for fluid ounce. 4  a small portion or amount.oun. 1  a unit of weight equal to one sixteenth of a pound (avoirdupois); 1 ounce is equal to 437.5 grains or 28.349 grams. 2  Abbreviation: oz. 3  a unit of weight equal to one twelfth of a Troy or Apothecaries' pound; 1 ounce is equal to 480 grains or 31.103 grams. 4  short for fluid ounce.