to Cicero, derived from relegare "go through again, read again," from re- "again" + legere "read" (see lecture
). However, popular etymology among the later ancients (and many modern writers) connects it with religare "to bind fast" (see rely
), via notion of "place an obligation on," or "bond between humans and gods." Another possible origin is religiens "careful," opposite of negligens. Meaning "particular system of faith" is recorded from c.1300.
"To hold, therefore, that there is no difference in matters of religion between forms that are unlike each other, and even contrary to each other, most clearly leads in the end to the rejection of all religion in both theory and practice. And this is the same thing as atheism, however it may differ from it in name." [Pope Leo XIII, Immortale Dei, 1885]
Modern sense of "recognition of, obedience to, and worship of a higher, unseen power" is from 1530s. Religious is first recorded early 13c. Transferred sense of "scrupulous, exact" is recorded from 1590s.