Lewis & Short

rāsūra, ae, f. [rastrum].

  1. I. Lit., a scraping, a shaving (post-Aug.): calami, Col. 4, 29, 9: barbae capitisque, Hier. in Isa. 5, 15, 2.
      1. 2. Concr., what is scraped or shaved off; a scraping, shaving: eboris, Veg. 1, 10, 6; 6 (4), 8, 8.
  2. II. Trop.: gulae, the harsh pronunciation of the gutturals by the Orientals, Hier. in Ep. Paul. ad Tit. 2, 9.