a.
1. [SUB- 14.] Below what is rational, less than rational.
1865. Daily Tel., 27 Nov., 2/3. The readiness … of a Tory, even of the sub-rational species, to entertain the question of Reform.
1896. Expositor, Sept., 214. [Man is] incomparable with ‘birds and four-footed beasts,’ and … with the entire subrational universe.
2. [SUB- 19.] Math. (See quot.)
1874–5. Cayley, Math. Papers (1896), IX. 315, note. The expression ‘subrational’ includes irrational, but it is more extensive; if Y, X are rational functions, the same or different, of y, x respectively, and Y is determined as a function of x by an equation of the form Y = X, then y is a subrational function of x.
