16-letter words starting with ac
- activation order — an instruction to create, mobilize, or organize a unit
- active directory — (operating system) A directory service from Microsoft Corporation, similar in concept to Novell Netware Directory Services, that also integrates with the user organisation's DNS structure and is interoperable with LDAP. Active Directory is included in Windows 2000.
- active transport — a process by which molecules are enabled to pass across a membrane from a region in which they are in a low concentration to one of high concentration; this requires the expenditure of energy in metabolism and is assisted by carrier proteins, commonly referred to as pumps
- activity holiday — a type of holiday in which holiday-makers can take part in many different organized activities, esp sports