A request from a clinical study sponsor to obtain authorization from the Food and Drug Administration (FDA) to administer an investigational drug or biological product to humans. Such authorization must be secured prior to interstate shipment and administration of any new drug or biological product that is not the subject of an approved New Drug Application or Biologics Product License Application. Unlike an EU CTA, an IND covers all trials related to an IP (and therefore must be updated when new trials are proposed).
Source: FDA