From <span class="searchmatch">Proto</span>-Indo-European *septm̥(m)ós, thematization of *septḿ̥. *<span class="searchmatch">septVmos</span> seventh Latin: septimus (see there for further descendants) Umbrian: 𐌔𐌄𐌕𐌖𐌌𐌔...
analogy to *<span class="searchmatch">septVmos</span> and *nowVnos, displacing older <span class="searchmatch">Proto</span>-Indo-European *deḱm̥tós > *dekəntos, which survived separately in Oscan. *dek<span class="searchmatch">Vmos</span> tenth *dekəntos...
From <span class="searchmatch">Proto</span>-Indo-European *septḿ̥. *septəm (indeclinable) seven *Septemos Latin: septem (see there for further descendants) Oscan: 𐌔𐌄𐌚𐌕𐌄𐌍 (seften)...