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dichotomous, a.|daɪˈkɒtəməs|
[f. L. dichotomos, -mus, a. Gr. διχότοµος cut in half, equally divided: see dicho- and -ous. Cf. F. dichotome (1752 in Hatz.-Darm.).]
Divided or dividing into two; characterized by dichotomy.
†1. Astron. = dichotomized 2; of the form of a half-moon. Obs.
1690Leybourn Curs. Math. 448 Mercury..in its greatest digression from the Sun..appears Dichotomous.
2. Bot., etc. Dividing into two equal branches; esp. so branched that each successive axis divides into two; relating to, or of the nature of, such branching.
1752Sir J. Hill Hist. Anim. 23 (Jod.) The short, dichotomous, horned monoculus. 1753Ellis in Phil. Trans. XLVIII. 116 These stretch out into many regular dichotomous branches. 1794Martyn Rousseau's Bot. xvii. 226 The Lesser Centaury..is distinguished by its dichotomous stalk. 1842E. Wilson Anat. Vade M. 262 The division of arteries is usually dichotomous. 1872Oliver Elem. Bot. ii. 185 Common Mistletoe..a dichotomous parasitical shrub, with opposite leathery leaves. 1882Vines Sachs' Bot. 170 Dichotomous branching is very common among Thallophytes, especially Algæ and the lower Hepaticæ.
3. Logic, etc. Of classification: Involving division (of a class or group) into two (lower groups); proceeding by dichotomy; dichotomic.
1838Sir W. Hamilton Logic xxv. (1866) II. 30 The division may be not only dichotomous but polytomous, as for example,—angles are right, or acute, or obtuse. 1864Reader 3 Sept. 304/2 The unities or molecules..are either isovoluminous or in what I have called dichotomous ratio. |