-illus

Meaning

1. morphemeUsed to form diminutives of nouns.
   furca f (“fork”) + -illus → furcilla f (“very small fork”)
   haedus m (“goat kid”) + -illus → haedillus m (“kidling, young kid”)

Origins

From the diminutive suffix -lus by rebracketing of nouns such as sigillum and pōcillum (diminutives of signum and pōculum). In words like these, -ill- was the regular phonetic outcome of earlier [n̩l] and [l̩l] (with syllabic [n̩] and [l̩]), which arose from adding the suffix -lus to stems that originally ended in a consonant + /n/ or /l/. After being reinterpreted as a suffix of its own, the ending -illus was attached freely to nouns of any form. Compare -ellus.