(Latin: one and a half; normally used as a prefix; from Latin, semis “half” + que “and”)
In chemistry, three atoms or equivalents of the [specified] element or radical are combined with two of another, as in iron sesquioxide, Fe 2O3. Also defined as the proportion of two (of one radical or element) to three (of another).
In astrology, having a zodiacal distance of about 108 degrees.
Of the ratio of 8 to 7, or 1 1/7 to 1.
Of the ratio of 7 to 6, or 1 1/6 to 1.
In music, a perfect fourth.
Of the ratio of 4 to 3.