Suppose a line meets sidelines , , and in points , , and , respectively. Let be the reflection of about the midpoint of segment , and construct and similarly. Then , , and are collinear in a line known as the isotomic transversal of (Kimberling 1998, p. 150).
An isotomic transversal is sometimes referred to as an isotomic conjugate (Ehrmann and van Lamoen 2004).