Seni, senæ, sena, A sex deriuatur. Cic.Sixe.Anni decies seni.Ouid.Three score yeares.
Lewis and Short: Latin dictionary
sēni, ae, a (gen. plur. senūm, Cic. Verr. 2, 49, 122; Caes. B. C. 2, 15), num. distrib. [sex]. I.Lit., six each: cum in sex partes divisus exercitus Romanus senis horis in orbem succederet proelio, Liv. 6, 4: senos viros singuli currus vehebant, Curt. 8, 14, 3: ut tribuni militum seni deni (by many written in one word, senideni) in quattuor legiones crearentur, Liv. 9, 30; so, sena dena (or senadena) stipendia, Tac. A. 1, 36 fin.: senūm pedum crassitudo, Caes. B. C. 2, 15; cf.: pueri annorum senūm septenūmque denūm,
sixteen and seventeen years old
, Cic. Verr. 2, 2, 49, 122.—II.Transf., for sex, six: tradiderat natalibus actis Bis puerum senis,
past his twelfth birthday
, Ov. M. 8, 243: sena vellera, id. ib. 12, 429: pedes, i. e.
hexameter
, Hor. S. 1, 10, 59: ictus (of the senarius), id. A. P. 253: latitudo ejus ne minus pedum senūm denūm (or senumdenum), Vitr. 6, 9.