a. (and sb.). Biol. [ad. mod.L. ūnicellulār-is (whence also F. unicellulaire): see UNI- and CELLULAR a.]
1. Composed or consisting of, having, a single cell; said esp. of the of the organisms belonging to the primary divisions of the animal and vegetable kingdoms.
Also in recent use as sb.
1858. Carpenter, Veg. Phys., § 35. The minute unicellular plants, known by the name of Diatomaceæ.
1875. Darwin, Insectiv. Pl., xiv. 329. All the leaves contained unicellular and other Algæ.
1892. Mivart, Ess. & Crit., II. 437. The distinction between unicellular and multicellular animals.
2. Characterized by the formation or presence of a single cell or cells.
1863. Dana, Man. Geol., 747. Plants in passing from the unicellular state by growth lose in power.
1892. J. Tait, Mind in Matter (ed. 3), 58. In the animal world colonies are the next approach of unicellular to multicellular organisation.
