Seculars are things that are not religious or spiritual. They are about regular, everyday life.
Seculars are often seen as separate from religion and are about normal, everyday things.
Examples:
The school teaches about math and science, but not about religious things, so it focuses on seculars.
In this country, the government is separate from religious groups, so it deals with seculars.
She likes to read books about history and nature, which are seculars.
The store sells both religious and secular books.
In this town, there are many buildings for religious things, but also many for seculars.
He likes to talk about religious things, but she prefers to talk about seculars.