These words refer to a married state in which someone has more than one spouse. Polygamy is a general term for any situation in which more than two people are knowingly joined in marriage. The word can refer to a husband with more than one wife, a wife with more than one husband, or to group marriages in which two or more husbands are married to two or more wives: a text dealing with varieties of polygamy in primitive cultures. Outside an anthropological context, the word is often understood to refer directly to the situation of a husband with two or more wives, since this departure from monogamy has been more widely dealt with (and perhaps practised) than other departures: the polygamy of the early Mormons. Polygyny would be the strict anthropological term for this situation in which two or more wives are married to one husband: linking the practice of polygyny with cultural assumptions about the innate inferiority of women; the disappearance of polygyny from Turkey with the emancipation of women.

By contrast, polyandry points specifically to the marrying of two or more husbands to one wife: matriarchal cultures that have polyandry as a concomitant. Bigamy refers as a legal term in Western civilization to the crime of being married to more than one spouse at the same time; the word functions for either sex. At first it might seem that the term is a legal divorce and marrying another while claiming to be unmarried. The word usually suggests a situation in which there is deception of at least one of the spouses, since few people in a monogamous society presumably consent to marry someone already married. Even in those instances where a deceiving bigamist sets up two households and alternates visits to both, a true situation of polygamy does not exist, since this word most often indicates spouses who knowingly share the same house-hold and are married to the same person as well.