Although "sex" and "having sex" also most commonly denote penile–vaginal intercourse, "sex" can be significantly broad in its meaning and may cover any penetrative or non-penetrative sexual activity between two or more people. The World Health Organization (WHO) states that non-English languages and cultures use different words for sexual activity, "with slightly different meanings". Various vulgarisms, slang, and euphemisms are used for sexual intercourse or other sexual activity, such as "fuck", "shag", and the phrase "sleep together". The laws of some countries use the euphemism "carnal knowledge." Penetration of the vagina by the erect penis is additionally known as "intromission", or by the Latin name " " (Latin for "insertion of the penis"). The age of first sexual intercourse is called "sexarche".