sex

UK: /ˈsɛks/ US: /sɛks/ ,(seks)

WordReference Random House Learner's Dictionary of American English © 2025

sex /sɛks/   n. 

1. either the female or male division of a species:
   [countable] What sex is your kitten?
2. all the differences by which the female and the male are distinguished;
   gender:
   [uncountable] discrimination on the basis of sex.
3. the attraction drawing one sex toward another:
   [uncountable] emphasis on sex in movies.
4. Medicine sexual intercourse :
   premarital sex.

Idioms

5. Medicine, Idioms have sex, to engage in sexual intercourse.

sex•less, adj. See -sect-.

sex-, prefix. 

1. sex- comes from Latin, where it has the meaning "six'':
   sexpartite (= having six parts or divisions).

WordReference Random House Unabridged Dictionary of American English © 2025

sex  (seks), n. 

1. either the male or female division of a species, esp. as differentiated with reference to the reproductive functions.
2. the sum of the structural and functional differences by which the male and female are distinguished, or the phenomena or behavior dependent on these differences.
3. the instinct or attraction drawing one sex toward another, or its manifestation in life and conduct.
4. Medicine coitus.
5. Medicine genitalia.
6. Medicine to have sex, to engage in sexual intercourse.

v.t. 

7. Animal Husbandry to ascertain the sex of, esp. of newly-hatched chicks.
8. sex up, [Informal.]
   • to arouse sexually:
     The only intent of that show was to sex up the audience.
   • to increase the appeal of;
     to make more interesting, attractive, or exciting:
     We've decided to sex up the movie with some battle scenes.

• Latin sexus, perh. akin to secāre to divide (see section)
• Middle English 1350–1400

sex  (seks), adj. [Latin.]

1. Foreign Terms six.

sex-, 

1. a combining form, occurring in loanwords from Latin, meaning "six'' (sexagenary);
   on this model used in the formation of compound words:
   sexpartite.

Also, sexi-. 

• Latin, combining form of sex six

Collins Concise English Dictionary © HarperCollins Publishers::

sex / sɛks/ noun

1. the sum of the characteristics that distinguish organisms on the basis of their reproductive function
2. either of the two categories, male or female, into which organisms are placed on this basis
3. short for sexual intercourse
4. feelings or behaviour resulting from the urge to gratify the sexual instinct
5. sexual matters in general

modifier

1. of or concerning sexual matters: sex education, sex hygiene
2. based on or arising from the difference between the sexes: sex discrimination

verb

1. (transitive) to ascertain the sex of

Etymology: 14th Century: from Latin sexus; compare secāre to divide

Collins Concise English Dictionary © HarperCollins Publishers::

sex- combining_form

1. six: sexcentennial

Etymology: from Latin