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Definition: Secular is an adjective meaning "long term" as in the phrase "secular trends." Outside the research context its more common meaning is 'not religious'.

Secular as an adjective means anything pertaining to the world that isn't religious, spiritual, or sacred. It has a temporal (set in real-time) context. So, for instance, in the separation of church and state debate, you might see legal (or other) reference to a public building being secular and precluding the display of non-secular items (such as the Ten Commandments). As a noun (that is, a proper word), it refers to a layperson (in a religious context most often) in a religious community. For example, an usher in a Christian-faith church service is a secular, as they have a function within the religious community, but no religious standing (as say, a minister or priest does and who fall in the category clergy).