Lewis & Short

† pȳrămis, ĭdis, f., = πυραμις (prob. Egyptian),

  1. I. a pyramid, Cic. N. D. 2, 18, 47; Prop. 3 1, 55; Mart. Spect. 1, 1; Tac. A. 2, 61; Plin. 36, 12, 16, § 75: pyramidas regum miramur, id. 36, 15, 24, § 103; Mel. 1, 9; Luc. 9, 155; Tac. A. 2, 61.
  2. II. Transf., a geometrical solid figure, a pyramid, Boëth. Arith. 2, 21 sqq.