TCG Letter #70

Tolkien had replied to William G. Harding about the word gemowe, Tolkien had no knowledge of this word prior to this exchange.^{Harding will also ask for details on another word, 'sag' and Tolkien replies to him on that later in the year. See Letter from J.R.R. Tolkien to Willard G. Harding • 21 October 1927 (#71)[1]}

The word 'gemowe' comes from the Latin geminus meaning twin and was used to describe two lines of equal length. Robert Recorde invented the equals sign in 1557 as there was no one form used to denote equals, he used long lines, three times the length of the modern equals sign which was adapted from his invention.