Latin quare clausum fregit (wherefore he broke the close, that is, trespass)
noun 1. (in the Nuclear Regulatory Commission) the highest level of security clearance, permitting access to secret information, documents, etc., relating to nuclear research.
quality control program plan
1. (in prescriptions) every day. q.d. abbr. Latin quaque die (every day) Latin quaque die (every day) Latin quasi dictat (as if he should say)