[too
sh; Ger. toosh-uh] 
| a greaselike liquid used in lithography as a medium receptive to lithographic ink, and in etching and silkscreen as a resist. |
| tu·sche (tŏŏsh'ə) n. A black liquid used for drawing in lithography and as a resist in etching and silk-screen work. [German, back-formation from tuschen, to lay on colors, from French toucher, from Old French tochier, touchier, to touch; see touch.] |