a. [f. the name of Dr. Robert Brown, who first described the movement in question.] Brownian movement: the irregular oscillatory movement observed in microscopic particles or ‘molecules’ of all kinds suspended in a limpid fluid; also called molecular movement.
1871. Bastian, Orig. Lowest Organisms, 46. Bacteria … which exhibit movements resembling those known as Brownian.
1874. Jones & Siev., Pathol. Anat., 28. Serum … crowded with fatty molecules, presenting an active Brownian movement.
1875. Darwin, Insectiv. Plants, iii. 64. Small granules which exhibited Brownian movements.
