Origin: Latin suffix -ular
Secular has 8 different meanings across 2 categories:
A secular ecclesiastic, or one not bound by monastic rules.
"The king appointed a secular priest to lead the parish church rather than assigning him to an abbey."
In plain English: A secular person is someone who does not follow any religion and makes decisions based on reason rather than faith.
"The school hired him to serve on its secular board, where he would focus only on non-religious matters."
of or relating to the doctrine that rejects religion and religious considerations
"The secular movement rejected all religious doctrines in favor of purely rational principles."
Not specifically religious; lay or civil, as opposed to clerical.
"The university is a secular institution where all students study regardless of their personal faith."
In plain English: Secular means not connected to religion or spiritual beliefs and focused on everyday life instead.
"The school is secular and does not teach any specific religion to its students."
Usage: Use secular primarily when describing matters that are non-religious and governed by the state rather than a church hierarchy. This term distinguishes civil institutions from those controlled by religious orders or clergy.
The word secular comes from the Latin saeculum through Old French and Middle English. Originally, it meant "of the age."