sex-, sexi-, sext-

(Latin: six, sixth; a word element for number 6)

Don't confuse this sex- with another one that refers to "mating" or "gender".

senary
sexadecimal
sexagenarian, sexagenarianism
Sixty years old or sixty to sixty-nine years of age.
sexagenary, sexagenaries
Sixty years of age; a person of from sixty to sixty-nine years old.; a person who is in his/her sixties.
sexagesima
sexagesimal
sexagonal
sexangular (sex-ANG-you-luhr) (adjective), more sexangular, most sexangular
Having six pronounced and visible divergent edges: Maurice had a supply of sexangular bricks which he planned to use to construct a special sitting area in his garden.
sexcentenary
sexdigital
Having six fingers and toes.
sexdigitate, sedigitate
Having an extra digit (six) on one or more hands or feet.
sexdigitism
The state of having six fingers on a hand, or six toes on a foot.
sexennarian
A six-year-old child.
sexennial
sexennially