infall /ˈɪnfɔːl/noun 4/ɪnˈfɔːl/ verb 2forms 4 noun4 •The act or process of falling in. •Movement towards a massive astronomical body under the influence of gravity; especially the process whereby gas falls towards a neutron star or black hole at high speed, forming a plasma •An incursion; an inroad.we learn that Ker , with his Western Army , was lying at a place called Carmunnock , when he made this infall upon Lambert — 1650 •The area where water, storm runoff, etc., enters a storm drain. infall /ɪnˈfɔːl/ verb2 •To fall in. •To undergo infall. formsinfell · infallen · infalling · infalls