What is Secular?

Secular definition and meaning on Dictionary terms:
of or relating to worldly things or to things that are not regarded as religious, spiritual, or sacred; temporal: secular interests.
not pertaining to or connected with religion (opposed to sacred): secular music.
(of education, a school, etc.) concerned with nonreligious subjects.
(of members of the clergy) not belonging to a religious order; not bound by monastic vows (opposed to regular).

occurring or celebrated once in an age or century: the secular games of Rome.
going on from age to age; continuing through long ages.

a layperson.
one of the secular clergy.