decagonum

From Ancient Greek δεκάγωνον (dekágōnon).

• (Classical) IPA^(key): /de.kaˈɡoː.num/, [d̪ɛkäˈɡoːnʊ̃ˑ]
• (modern Italianate Ecclesiastical) IPA^(key): /de.kaˈɡo.num/, [d̪ekäˈɡɔːnum]

decagōnum n (genitive decagōnī); second declension

1. (Medieval Latin, geometry) decagon
   • c. 1308–1336, Richard of Wallingford, “Quadripartitum Ricardi Walynforde de Sinibus Demonstratis”, in John David Bond, editor, Isis, volume 5, number 1, published 1923, →JSTOR, page 108:

     Tunc ${\displaystyle id}$ cōnstābit ex medietāte sēmidiametrī et ex latere decagōnī eiusdem circulī, quod sīc probātur.

     Then ${\displaystyle id}$ will be composed from half the semidiameter [radius] and from the side of the decagon of the same circle, which is proved in this way.

Second-declension noun (neuter).

• R. E. Latham, D. R. Howlett, & R. K. Ashdowne, editors (1975–2013), “decagonum”, in Dictionary of Medieval Latin from British Sources‎, London: Oxford University Press for the British Academy, →ISBN, →OCLC