-cule

Also ‑cle, ‑icle, and ‑culus.

Forming nouns.

French ‑cule, derived from Latin ‑culus, ‑cula or ‑culum.

The original sense of the Latin endings was as a diminutive, though this has largely been lost in English. Words in ‑cule include graticule (Latin cratis, a hurdle), a series of fine lines used as a measuring scale; molecule (Latin moles, mass), a group of atoms bonded together. Words in ‑cle (of which ‑icle is a variant in which the i is contributed by the Latin stem) include article, particle, carbuncle, cubicle, manacle, and testicle.

Some words exist in more than one form, with those in ‑(i)cle being more general than those in ‑cule or ‑culus (the latter perpetuating the masculine form of the Latin ending), which are commoner in scholarly contexts. An example is fascicle (from Latin fascis, a bundle) for an instalment of a printed book, which sometimes appears as fascicule; in anatomy and biology the word is more commonly fasciculus for a bundle of structures, such as nerve fibres or conducting vessels.

Words that primarily exist in the ‑ulus ending include homunculus (Latin homo, man), a very small human figure; the genus of the bindweed, convolvulus (literally a little thing bound together); and apiculus, a minute point or tip.