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.
| 1690 Leybourn 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.
| 1752 Sir J. Hill Hist. Anim. 23 (Jod.) The short, dichotomous, horned monoculus. 1753 Ellis in Phil. Trans. XLVIII. 116 These stretch out into many regular dichotomous branches. 1794 Martyn Rousseau's Bot. xvii. 226 The Lesser Centaury..is distinguished by its dichotomous stalk. 1842 E. Wilson Anat. Vade M. 262 The division of arteries is usually dichotomous. 1872 Oliver Elem. Bot. ii. 185 Common Mistletoe..a dichotomous parasitical shrub, with opposite leathery leaves. 1882 Vines 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.
| 1838 Sir 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. 1864 Reader 3 Sept. 304/2 The unities or molecules..are either isovoluminous or in what I have called dichotomous ratio. |