Source — Euclid's Elements, encoded as an rrxiv paper

X.II.1 Definition X.II.1

Given a rational straight line and a binomial, divided into its terms, let the square of the greater term be greater than the square of the lesser by the square of a straight line commensurable in length with the greater. Then if the greater term is commensurable in length with the assigned rational straight line, the whole is called a first binomial.

lines 74–74 in main.tex