1610s, "worship, homage" (a sense now obsolete); 1670s, "a particular form or system of worship;" from French culte (17c.), from Latin cultus "care, labor; cultivation, culture; worship, reverence," originally "tended, cultivated," past participle of colere "to till" (see colony).
The word was rare after 17c., but it was revived mid-19c. (sometimes in French form culte) with reference to ancient or primitive systems of religious belief and worship, especially the rites and ceremonies employed in such worship. Extended meaning "devoted attention to a particular person or thing" is from 1829.
Cult. An organized group of people, religious or not, with whom you disagree. [Hugh Rawson, "Wicked Words," 1993]
Cult is a term which, as we value exactness, we can ill do without, seeing how completely religion has lost its original signification. Fitzedward Hall, "Modern English," 1873]