the act of sexual procreation between a man and a woman; the man's penis is inserted into the woman's vagina and excited until orgasm and ejaculation occur
例句
用作名词(n.)
One part of this relationship is sexual intimacy.这个关系的一部分是有关性关系的。
They were not having a sexual relationship at the time.当时他们之间并不存在性关系。