sesquitertia

Noun

 * 1)  A ratio of 4 to 3.
 * 2) * 1570,, in H. Billingsley (trans.) Euclid, Elements of Geometry, Preface:
 * For, what proportion, 100 hath to 75: the same hath 17 1/7 to 12 6/7: Which is Sesquitertia: that is, as 4, to 3. which make 7.
 * 1)  A perfect fourth, an interval having the ratio of 1 to 1⅓, or 3 to 4.