rotundus

• retundus

Generally regarded as deriving from rotō (“turn, revolve”) or rota (“wheel”) +‎ -undus. First attested in the works of Cato the Elder (circa 200 BC).

It has also been suggested that the alternative form retundus, whence most of the Romance descendants derive, actually reflects the original Latin form (despite only being attested from the seventh century CE). If so, the first element would derive from an older *retō, from Proto-Indo-European *Hreth₂- (cf. Proto-Celtic *reteti), and the Classical rotundus would reflect later influence from rota (“wheel”).[1]

• (Classical) IPA^(key): /roˈtun.dus/, [rɔˈt̪ʊn̪d̪ʊs̠]
• (modern Italianate Ecclesiastical) IPA^(key): /roˈtun.dus/, [roˈt̪un̪d̪us]

rotundus (feminine rotunda, neuter rotundum, comparative rotundior, superlative rotundissimus); first/second-declension adjective

1. round, circular
2. spherical, rotund
3. (figuratively) rounded, perfect
4. (figuratively, of speech) polished, elegant

First/second-declension adjective.

(See also retundus, *torundus.)

• Insular Romance:
  • Sardinian: rodundu, orrudundu (both medieval)
• North Italian:
  • Lombard: rodond
  • Romansch: rodund
• Gallo-Romance:
  • >? Old Catalan: rodon (if not from retundus, with later assimilation)
    • Catalan: rodó
  • Old Franco-Provençal: raond
  • Old French: roont, ruunt
• Ancient borrowings:
  • → Albanian: urtundë
• Later borrowings:
  • → Catalan: rotund
  • → English: rotund
  • → French: rotond
  • → Italian: rotondo
  • → Portuguese: rotundo
  • → Romanian: rotund
  • → Spanish: rotundo

• “rotundus”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “rotundus”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers
• rotundus in Gaffiot, Félix (1934) Dictionnaire illustré latin-français, Hachette.