random movement of microscopic particles suspended in a fluid, caused by bombardment of the particles by molecules of the fluid. First observed in 1827, it provided strong evidence in support of the kinetic theory of molecules
Word origin
C19: named after Robert Brown
Brownian movement in American English
(ˈbraʊniən)
the constant, random, zigzag movement of small particles dispersed in a fluid medium, caused by collision with molecules of the fluid
: also Brownian motion
Word origin
after R. Brown (1773-1858), Brit botanist who described it