• secius, sequius, sectius (confusions with the comp. of secus)

From Proto-Italic *sētos (“late”), from Proto-Indo-European *seh₁- (“late, long”). Cf. sērus, with a different extension. Cognate to Old Irish sith- (“continuous”), Welsh hyd (“length”), Gothic 𐍃𐌴𐌹𐌸𐌿𐍃 (seiþus, “late”), Old English sīd (“broad”).

sētius (not comparable)

1. later, slower
2. (with negatives) to a lesser degree, less readily
   • c. 37 BCE – 30 BCE, Vergilius, Georgicon 3.366–367:

     […] Stiriaque impexis induruit horrida barbis,
     Interea toto non setius aere ningit.

     […] hoarfrost clings to their uncombed, shaggy beards while the whole sky keeps on sheding snow.

3. (influenced by secus) otherwise

• nihilō sētius (“none the less”)
• quō sētius (“so as to prevent”)

• “sētius” on page 1929 of the Oxford Latin Dictionary (2nd ed., 2012)
• De Vaan, Michiel (2008), “sētius”, in Etymological Dictionary of Latin and the other Italic Languages (Leiden Indo-European Etymological Dictionary Series; 7), Leiden, Boston: Brill, →ISBN, page 559

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