(1)The act of being assimilated; usually by the Borg. Or, (2)the absorbtion of a foreign body into a living being.
(1) This is the Borg. You will be assimilated. We will add your biological and technological distinctions to our own. You will adapt to service us. Resistance is futile.
or (2) I assimilated that bullet you shot me in the leg with.