grot Copy link Outline 1. antrum2. mūsēum (a g. made of rock-work) • grot, grotto: 1. antrum: 'neath the pleasant g., grato sub a., Hor.: stretched out at full length in the verdant g., viridi projectus in a., Virg. 2. mūsēum (a g. made of rock-work): Plin. 36, 21, 42. See also cave.