effusion

ef·fu·sion

noun \i-ˈfyü-zhən, e-\

Definition of EFFUSION

1

a : the escape of a fluid from anatomical vessels by rupture or exudation b : the flow of a gas through an aperture whose diameter is small as compared with the distance between the molecules of the gas

2

: the fluid that escapes by extravasation—see pleural effusion