sext v.

one more than five; twice three; the number which is one more than five; a symbol representing this number;" Old English siex, six, seox, sex, from Proto-Germanic *seks (source also of Old Saxon and Danish seks, Old Norse, Swedish, and Old Frisian sex, Middle Dutch sesse, Dutch zes, Old High German sehs, German sechs, Gothic saihs), from PIE *s(w)eks (source also of Sanskrit sas, Avestan kshvash, Persian shash, Greek hex, Latin sex, Old Church Slavonic sesti, Polish sześć, Russian shesti, Lithuanian šeši, Old Irish se, Welsh chwech).

As "playing card with six spots or pips" by 1590s. Six-footer "person measuring six feet or more" is by 1828. Six-shooter, usually a revolver with six chambers (firing six shots in succession), is attested from 1842; six-pack of beverage containers is from 1952, of abdominal muscles by 1995.

[Married] In Dana, [Mass.], on the 30th ult. by Ephraim Whipple, Esq. Mr. Jason W. Williams, M. D. to Miss Malinda Chamlin, of Dana,—a couple of six footers. Printers in New York, Ohio, Alabama, Vermont, Connecticut, Rhode-Island, New Hampshire and Maine, are requested to publish the same marriage, that his brothers and sisters may have due notice thereof and rejoice accordingly. [Burlington, Vt., Weekly Free Press, Feb. 8, 1828]

Six of one and half-a-dozen of the other "little difference" is recorded from 1833. Six-figure (adj.) in reference to hundreds of thousands (of dollars, etc.) is from 1840. Six feet under "dead" is from 1942.

The phrase at sixes and sevens originally was "hazarding all one's chances," first in Chaucer, perhaps from dicing (the original form was on six and seven); it could be a corruption of at cinque and sice "exposed to great risk" (1530s), literally "at five and six," using the French names (which were common in Middle English) for the highest numbers on the dice. The meaning "at odds, in disagreement or confusion" in the exact phrase is from 1785; in Middle English the phrase set at (or on) six and seven meant "play havoc, create an uproar."

late 14c., "males or females considered collectively," from Latin sexus "a sex, state of being either male or female, gender," a word of uncertain origin. "Commonly taken with seco as division or 'half' of the race" [Tucker], which would connect it to secare "to divide or cut" (see section (n.)).

Secus seems the more original formation, but it is strange that the older texts only know sexus. The modern meaning of sectiō 'division' suggests that sec/xus might derive from secāre 'to sever', but the morphology remains unclear: does sexus go back to an s-present *sek-s- 'to cut up', or was it derived from a form *sek-s- of the putative s-stem underlying secus? [Michiel de Vaan, "Etymological Dictionary of Latin and the other Italic Languages," Leiden, 2008]

The meaning "quality or character of being either male or female" with reference to animals is recorded by 1520s; by 19c. this meant especially "the anatomical distinction between male and female as evidenced by physical characteristics of their genital organs and the part taken by each in reproduction." Extended by 1560s to characteristics or structures in plants which correspond to sex in animals.

It is curious that the Anglo-Saxon language seems to have had no abstract term for sex, which was expressed only severally as manhood or womanhood. [Thomas Wright, note to "Anglo-Saxon and Old English Vocabularies," 1884] 

Also especially the sex "the female sex, womankind" (1580s). The meaning "sexual intercourse" (have sex) is by 1906; the meaning "genitalia" is suggested by 1933 ("Fumes of Formation") and probably is older. Sex symbol by 1871 in anthropology; the first person to whom the term was applied seems to have been Marilyn Monroe (1959). Sex-kitten is attested by 1954 (Brigitte Bardot). Sex object is by 1901, originally in psychology; sex appeal is attested by 1904.

For the raw sex appeal of the burlesque "shows" there is no defense, either. These "shows" should be under official supervision, at the least, and boys beneath the age of eighteen forbidden, perhaps, to attend their performance, just as we forbid the sale of liquors to minors. [Walter Prichard Eaton, "At the New Theatre and Others: The American Stage, Its Problems and Performances," Boston, 1910]

Sex-life is attested by 1887. Sex-drive is by 1916 (sex-impulse by 1911). Sex-education is by 1894; sex therapist is by 1969, in early use often in reference to Masters and Johnson. Sex-crime is by 1907; sex-maniac by 1895; sex-fiend by 1931 (in a New York Daily News headline).

"to send a text message by mobile system," 2005; see text (n.). Related: Texted; texting. Formerly it meant "to write in text letters" (1590s), text letters being a kind of large writing used by clerks in the text or body of a manuscript (distinguished from the smaller hand used in the notes).