ORDO is applied to any body of men who form a distinct class in
the community, either by possessing distinct privileges, pursuing
certain trades or professions, or in any other way. Thus the whole
body of sacerdotes at Rome is spoken of as an ordo, and separate
ecclesiastical corporations are called by the same title. The
libertini and scribae also formed separate ordines. The senate and
the equites are also spoken of respectively as the ordo senatorius
and ordo equestris, but this name is never applied to the plebes.
Accordingly we find the expression, _uterque ordo_, used without
any further explanation to designate the senatorial and equestrian
ordines. The senatorial ordo, as the highest, is sometimes
distinguished as _amplissimus ordo_.--The senate in colonies and
municipia was called _ordo decurionum_ [COLONIA], and sometimes
simply _ordo_.--The term ordo is also applied to a company or troop
of soldiers, and is used as equivalent to centuria: thus centurions
are sometimes called _qui ordines duxerunt_, and the first centuries
in a legion _primi ordines_. Even the centurions of the first
centuries are occasionally called _primi ordines_.