Lewis & Short

rūtrum, i, n. [ruo, cf. Varr. L. L. 5, § 134 Müll.].

  1. I. An implement for digging, a spade, shovel, Cato, R. R. 10, 3; 11, 4; Varr. and Pompon. ap. Non. 18, 22 sq.; Liv. 28, 45; Ov. F. 4, 843.
  2. II. For mixing mortar, a trowel, Cato, R. R. 128; Vitr. 7, 3; Plin. 36, 23, 55, § 177; Pall. 1, 15.