- (Classical) IPA(key): /ku.lus/, [kʊɫ̪ʊs̠]
- (Ecclesiastical) IPA(key): /ku.lus/, [kulus] (stressed on the antepenult (third-to-last syllable); e.g., māsculus /ˈmaːs.ku.lus/)
- Alternative form of
The ending -culus occurs originally and frequently in diminutives formed from third declension nouns with stems ending in /n/ or /s/.  It is used also with other third declension nouns, in particular r-stems, l-stems, and i-stems, and with fourth and fifth declension nouns. In the form -iculus, it is sometimes used instead of -ulus to form diminutives of other consonant stem nouns or of first or second declension nouns. As with other Latin diminutive suffixes, the gender of the diminutive regularly matches the gender of the base noun.
The stem that the diminutive is built on sometimes differs from the stem found in the genitive singular of the base:
- Some consonant-stem nouns with a genitive singular ending in -ris form diminutives in -s-cul-. The majority are original s-stem nouns that developed -r- in the oblique stem due to the sound change of rhotacism. Synchronically, it may also be relevant that original stem-final s was usually retained in the nominative singular form of a neuter noun. However, the frequent ending -uscul- was sometimes extended by analogy to the diminutive of nouns that were not etymologically s-stems, such in marmusculum (from the r-stem marmor) and rāmusculus (from the o-stem rāmus).
- N-stem nouns (most of which have nominatives ending in -ō and oblique stems ending in -ōn- or -in-) form diminutives in -un-cul-, due to regular sound changes that turned ō or o into u before the cluster /nk/. After -uncul- developed in the diminutives of stems where /n/ was originally preceded by ō or o, this vocalism was extended by analogy to diminutives from stems that originally had other vowels before the stem-final /n/.
- The suffix may be preceded by a vowel:
- Some consonant-stem nouns form diminutives that include the short vowel /i/ before the -c- of the diminutive suffix (such as anaticula, from anas); on the other hand, some i-stem nouns form diminutives that lack the stem vowel -i- (such as animalculum, from animal).
- Diminutives of fourth declension nouns regularly replace the /u/ at the end of the noun's stem with /i/, as in acicula, corniculum and geniculum (from acus, cornū, genū).
- A small number of nouns, such as canīcula, irregularly add the long vowel -ī-.
- Some third declension nouns with nominative singular forms ending in -ēs, such as nūbēs, form diminutives in -ēcul-, such as nūbēcula.
- ōs, ōris n (“mouth”) + -culus → ōsculum n (“little mouth”)
- lepus, leporis m (“hare”) + -culus → lepusculus m (“young hare, leveret”)
- arbor, arboris f (“tree”) + -culus → arbuscula f (“shrub”)
- uxor, uxōris f (“wife”) + -culus → uxorcula f (“little wife”)
- sermō, sermōnis m (“talk, rumor”) + -culus → sermunculus m (“rumor; small talk”)
- carō, carnis f (“flesh”) + -culus → caruncula f (“little bit of flesh”)
- clāvis, clāvis f (“key”) + -culus → clāvicula f (“little key”)
|Case / Gender||Masculine||Feminine||Neuter||Masculine||Feminine||Neuter|
- -unculus (rebracketing)
- ^ Derivation of Adjectives: Nominal Adjectives in Meagan Ayer, Allen and Greenough’s New Latin Grammar for Schools and Colleges. Carlisle, Pennsylvania: Dickinson College Commentaries, 2014.
- ^ "The Formation of Latin Diminutives of Nouns and Adjectives," Ian Andreas Miller, ResearchGate, Jan 2012