The Torah in Parashat Emor (Vayikra 21:7) forbids a Kohen from marrying a “Zona.” The Sefer Ha’hinuch explains that this refers to a woman who falls into any one of the following three categories: 1) she is not Jewish; 2) she had a forbidden relationship at any point in the past; 3) she had a relationship with a “Halal,” a Kohen who was the product of a marriage which is forbidden for Kohanim (such as between a Kohen and a divorcee). Even though a woman is permitted to marry a “Halal,” nevertheless, such a relationship renders the woman a “Zona” with respect to the prohibition against a Kohen’s marriage to a “Zona.” The reason behind this command, the Sefer Ha’hinuch writes, is because the Kohanim were designated to serve G-d at all times, and they must therefore live on a higher standard of purity and sanctity. The choice of a marriage partner, of course, has a profound effect on a person’s life, and in fact, a person has his or her marriage partner on his or her mind throughout the day. Therefore, if a Kohen is married to a “Zona,” a woman who might likely have a negative influence on him, this will compromise his level of sanctity. Moreover, it will undermine the dignity and prestige of the priesthood, because people will likely know about this woman’s past, and will now associate the Kohen with her. Not all forbidden relationships render a woman a “Zona” with respect to this prohibition. First, the relationship must be of the type which is forbidden for all people, and not for only some people. For example, if a widow married a Kohen Gadol (a marriage which the Torah forbids), she does not become a “Zona,” because this kind of marriage is forbidden only for a Kohen Gadol, and not for others. A woman becomes a Zona by having a forbidden relationship even if the relationship does not constitute a capital offense. For example, if she has a relationship with a gentile, a non-Jewish servant, a Mamzer, or a convert from Amon, Moab or Edom, she has not committed a capital offense, but she nevertheless is now considered a “Zona” and may not marry a Kohen, because these relationships are forbidden. An intimate relationship with an animal, though it obviously constitutes a grievous offense, does not render a woman a “Zona.” Likewise, having relations while unmarried, or having relations while a Nidda, does not render her a “Zona.” A forbidden relationship renders the woman a “Zona” as long as she was at least three years old and the male was at least nine years. She attains this status already at the first stage of intercourse (“He’ara”), and even if she engaged in intercourse “She’lo Ke’darkah” (not in the usual manner). This prohibition applies to Kohanim, in all times and in all places. A Kohen who has relations with a woman who falls under the category of “Zona” is liable to Malkut.