a. (and sb.) [f. BI- pref.2 + MEDIAL, f. L. medi-us middle.]
† a. Algeb. (See quot. 1557.) Obs. b. Geom. The sum of two medial lines; a medial line being the geometric mean between two incommensurable lines, which have commensurable squares.
1557. Recorde, Whetst., P p iv. The nombers that be compounde with +, be called Bimedialles … And if the Bimedialles haue all their nombers and partes of one denominations, then bee thei called onely by their general name Bimedialles. But if their partes be of 2 denominations, then are thei named Binomialles properly. Howbeit, many vse to call Binomialles all compounde nombers that haue +.
1570. Billingsley, Euclid, X. lxvii. 278. A line commensurable in length to a bimediall line, is also a bimediall lyne and of the selfe same order.
1727. Chambers, Cycl., s.v. Bimedial, When two medial lines, as AB and BC, commensurable only in power, and containing a rational rectangle, are compounded; the whole AC shall be irrational, and is called a first bimedial line. [So in later Encycl.]
