2. (Geol.) Later than, or subsequent to, the Tertiary; Post-tertiary;
as, the Quaternary age, or Age of man.
Qua*ter"na*ry, n. [L. numerus quaternarius: cf. F. quaternaire.] 1. The
number four. Boyle.
2. (Geol.) The Quaternary age, era, or formation. See the Chart of
Geology.
Qua*ter"nate (?), a. Composed of, or arranged in, sets of four;
quaternary; as, quaternate leaves.
Qua*ter"ni*on (?), n. [L. quaternio, fr. quaterni four each. See
Quaternary.] 1. The number four. [Poetic]
2. A set of four parts, things, or person; four things taken
collectively; a group of four words, phrases, circumstances, facts, or
the like.
Delivered him to four quaternions of soldiers.
Acts xii. 4.
Ye elements, the eldest birth Of Nature's womb, that in quaternion
run.
Milton.
The triads and quaternions with which he loaded his sentences.
Sir W. Scott.