1) Action 2) Activity 3) Breaking up a military unit 4) Natural action 5) Natural process 1) Deactivation 
(from the article `nervous system`) A series of nerve impulses arriving in rapid succession at the axon terminal is accurately reproduced as a series in the postsynaptic cell because ...
<neurology, physiology> For example of voltage gated sodium channels: process by which sodium channels that have been activated or opened by depolarisation subsequently close during the depolarisation. Distinguished from activation by its slower kinetics. ... (18 Nov 1997) ... 
(in-ak″tĭ-va´shәn) the destruction of activity, as of a virus, by the action of heat or another agent. X-chromosome inactivation , X-inactivation lyonization.
For example, of voltage-gated sodium channels: process by which sodium channels that have been activated or opened by depolarization subsequently close during the depolarization. Distinguished from activation by its slower kinetics.
Type: Term Pronunciation: in′ak-ti-vā′shŭn Definitions: 1. The process of destroying or removing the activity or the effects of an agent or substance; the complementary effect of a serum may be destroyed by means of inactivation at 56°C for 30 minutes.
[n] - the process of rendering inactive
noun breaking up a military unit (by transfers or discharges)