invisible ink


invisible ink

n. Ink that is colorless and invisible until treated by a chemical, heat, or special light. Also called sympathetic ink.

invisible ink

n (Chemistry) a liquid used for writing that does not become visible until it has been treated with chemicals, heat, ultraviolet light, etc

invis′ible ink′


n. a writing fluid that is invisible until treated, as by heat or chemicals. [1675–85]
Translations
inchiostro simpatico