In English, “religion” is the most common, catch-all term to refer to any organized group that worships a higher power.
It is at the center of some of modernity’s most-heated controversies on the subjects of freedom, reason, morality, culture, and violence, and is a word that often inspires polar reactions of both respect and scorn.
Given the centrality of “religion” in human affairs, and the passions which it stirs in people, you’d think that we would have a clear idea about the etymology of the term.
But we don’t—a fact that annoyed Thomas Paine, who lamented that “the word religion is a word of forced application when used with respect to the worship of God.”
The etymological source of the term “religion”—which comes from the Latin noun religio (there isn’t really a precisely corresponding term in the Greek or Hebrew)—has been an ongoing subject of debate in the West since ancient times, and we’re still no closer to a resolution.
Many authors today will confidently claim that the word “religion” comes from the Latin verb religare, which means “to bind”. This interpretation can be traced back to the Christian philosopher Lactantius (240-320 AD), who wrote that religion gets its name from the ongoing act of a person “binding himself to God.”
But that’s really just a theory, as is another popular interpretation that traces back to Cicero (106-43 BC). In his De Natura Deorum, Cicero links “religion” to the Latin verb relegere, which means “to go through or over again in reading, speech, or thought.” The later Christian author Isidore (560-636 AD) writes, “According to Cicero, a man is said to be religious from religio, because he often ponders over, and, as it were, reads again [relegit], the things which pertain to the worship of God.”
A third interpretation, pointed to by St. Thomas Aquinas, derives from Augustine (354-430 AD) in the City of God, where he claims that “religion” comes from the Latin verb religere meaning “to recover.” “Having lost God through neglect [negligentes],” he writes, “we recover Him [religentes] and are drawn to Him.” (Augustine later retracted this etymological explanation of “religion” in favor of Lactantius’.)
Of course, the etymological confusion surrounding “religion” doesn’t mean that we aren’t entitled to still use the word to refer to a system of faith and worship. Language, after all, is what’s called a “conventional sign”: it acquires its meaning from custom.
But I'll say this: it’s a bit humorous that the confusion seems to be mirrored in most people’s actual understanding of religion