1 : (law) the principle that an act done at a later time is deemed by law to have occurred at an earlier time; "his attorney argued for the relation back of the amended complaint to the time the initial complaint was filed"
2 : a person related by blood or marriage
3 : 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
