Non-Disclosure Agreement 
National Defense Area 
New Drug Application 
National Democratic Alliance 
National Directory Assistance 
Non Disclosure Agreement 
Nuclear Decommissioning Authority 
Network Design Aid 
Nondisclosure Agreement 
nalidixic acid 
Naphthalene-2,3-dialdehyde 
Naphthalene-2,3-dicarboxaldehyde 
Naphthaline Dicarboxylic Acid 
National Dairy Authority 
National Dairymen's Association 
National Defense Academy 
National Defense Act 
National Demining Agency 
National Dental Association 
National Department of Agriculture 
National Doctors Alliance 
N-desethylamiodarone 
Net Domestic Asset 
Net Domestic Assets 
Network Delivery Access 
Nevada Development Authority 
New Drug Approval 
Nigerian Defence Academy 
Nightly Difference Analysis 
no detectable activity