•a sixth, particularly · sextans, a unit of mass equal to 1/6 libra (Roman pound) or 2 uncia (Roman ounce), about 55 g · sextans, a unit of area equal to 1/6 juger or 1/3 actus, equivalent to a rectangle with sides of 120×40 pedes (Roman feet), about 420 m²
köken: Learned borrowing from Latin sextus, along with several other ordinal numerals (segundo, quinto, séptimo), a tendency shared with many other Romance languages. Compare the inherited feminine doublets, sesma and siesta.
By surface analysis, sex (“six”) + -āns. According to the linguist Albio Cassio, it is more probably a calque of Ancient Greek ἑξᾶς (hexâs), though the Greek forms are more often explained as borrowings from the Latin.