Section 23.1: LyX Up Chapter 23: This Manual Section 23.3: LaTeX 

23.2 TeX

The TeX typesetting application is the result of nearly 20 years of work by Donald Knuth, Professor Emeritus of Stanford University who put it into the public domain. Knuth is the author of the famous quintet of books entitled The Art of Computer Programming which has been the staple text of university computer science courses for over 20 years. Knuth derived the name TeX from the Greek word (techne) which means both art and skill.
In Greek: τϵχνη
It is pronounced tek but as Knuth says: if you say it aloud, the computer screen should become moist. (The Greek letter X (chi) sounds a bit like the ch in loch). Knuth wrote TeX because he was concerned at the poor quality of the typesetting of the early editions of his own books and at the expense of getting it done correctly. The stated aim of TeX is to produce beautiful books.
 Section 23.1: LyX Up Chapter 23: This Manual Section 23.3: LaTeX