Coss /(kŏs)/

Coss

n.
  1. A Hindoo measure of distance, varying from one and a half to two English miles.

Coss

n.
  1. A thing (only in phrase below).

Phrases & Compounds
Rule of Coss
an old name for Algebra. [It. regola di cosa rule of thing, the unknown quantity being called the cosa, or the thing.]