petra¹

1. Saxum, rupes, and cautes, are greater; lapis, calx, and scrupus, smaller masses of stone. Plin. H. N. xxxvi. 22. Silex viridis ubi invenitur, lapis, non saxum est. 2. Saxa (from ψεκάς, ψήχω) are greater masses of stone, in whatever form, like πέτραι; rupes and petræ (πέτραι, from πεσεῖν) are steep and high, like rocks, and therefore difficult to climb; cautes and scopuli are rough and pointed, like crags, and therefore threaten danger; the cautes are smaller, and also not visible in the water, and therefore deceitful; the scopuli (from κόψαι) jutting upwards, threaten and announce danger, like σκόπελοι. 3. Lapis (ἄλιψ) is the most general expression, and denotes the stone only as a material substance, without regard to its form, like λίθος; calculus, is a smooth, generally round pebble; scrupulus, a rough, generally angular pebble; but for this meaning of scrupulus, the dimin. of scrupus, we have only the authority of grammarians; in authors it has only the figurative meaning of scruple. (v. 191.)