A parliamentarian is an expert on parliamentary procedure who advises organizations and deliberative assemblies. This sense of the term "parliamentarian" is distinct from the usage of the same term to mean a member of Parliament.
Some parliamentarians are officers or employees of the deliberative assembly that they serve, as in the case of the Parliamentarian of the United States Senate. Others have a contractual relationship, much like outside attorneys or accountants. They may be called in to assist in drafting bylaws, for instance. The parliamentarian should unobtrusively call the attention of the presiding officer to serious errors in procedure. However, the advice of a parliamentarian is generally not binding on the presiding officer of an assembly. The highest certifications of parliamentarians are the Professional Registered Parliamentarian, or PRP (issued by the National Association of Parliamentarians) and the Certified Professional Parliamentarian, or CPP, or the Certified Professional Parliamentarian Teacher, or CPP-T (both issued by the American Institute of Parliamentarians).
In most state legislative bodies, the secretary or chief clerk of the body serves as parliamentarian.
See also 
- RONR (10th ed.) p. 539
- National Conference of State Legislatures (2000). Mason's Manual of Legislative Procedure, 2000 ed., p. 430