A 14-year-old Iraqi girl, who uses the alias Narin, was given to a member of the Islamic State as his wife. Narin escaped and is hiding in the Iraqi region of Kurdistan.

On Thursday morning, John F. Kerry issued a statement that said the Islamic State militant group had committed atrocities against minority groups in Iraq and Syria that constitute genocide. The U.S. secretary of state's comments marked the first such U.S. declaration since 2004, when then-Secretary of State Colin Powell said the killings taking place in Sudan's Darfur region amounted to genocide.

The concept of genocide carries a lot of weight in international law. The 1948 U.N. convention on genocide requires signatories to work to prevent genocide and punish perpetrators when it does occur.

However, while the United Nations defines the term as "acts committed with intent to destroy, in whole or in part, a national, ethnical, racial or religious group," it does not cover systematic violence against a particular sex. And according to one French lawmaker, the violence being committed by the Islamic State against women is so systematic and so ferocious that it needs a new term in international law to define it: femicide.

Speaking Wednesday at the 60th annual Commission on the Status of Women at the United Nations in New York, Laurence Rossignol, France's minister for family, children and women's rights, pointed to the harsh conditions for Yazidi women in Islamic State-held territory. "It is because they are women and they are Yazidis that they are sold and murdered," Rossignol said, according to Radio France International. "What they are experiencing is femicide."

She also pointed to the kidnapping of women by Boko Haram fighters in Nigeria as examples of femicide.

The term femicide has been used for centuries to refer to the killing of women, but it was reclaimed during the feminist movement of the 1970s to refer more specifically to the systematic violence against women because of their sex. Diana Russell, the South African-born writer and activist who was an early proponent of the term, came to define it as "the killing of females by males because they are female."

There seems to be little doubt that the violence against Yazidi women is committed because they are female. As my colleague Ishaan Tharoor noted earlier, when the Islamic State seized areas in which the largely Kurdish-speaking minority lived, they rounded up young women and took them away. An estimated 5,000 were captured in 2014 alone and placed in an elaborate system designed to transport, house and trade female slaves, with women bought and sold like commodities based on their perceived sexual value.

Multiple accounts suggest that women who tried to escape risked being killed, while others faced death if they refused to engage in sometimes extreme sexual acts. "They are institutionalizing sexual violence," Zainab Bangura, the United Nations' special representative on sexual violence in conflict, said last year of the Islamic State. "The brutalization of women and girls is central to their ideology."

The United Nations has encouraged countries to pass domestic legislation that would target violence against women and, more specifically, femicide. To date, more than 100 countries have laws that seek to tackle the former. But what Rossignol is suggesting is something at the international level. She wants femicide to become the "basis for prosecution in international courts," RFI reports, and eventually be used in the International Criminal Court, which was set up in 2002 to try international crimes such as genocide and crimes against humanity.

Rashida Manjoo, the U.N. special rapporteur on violence against women, and others have in the past called for a U.N. treaty that would address violence against women. Writing recently at the Conversation, Ronagh McQuigg, a professor of law at Queen's University Belfast, acknowledged that a treaty on violence against women would probably take years to develop and may well run into the same problems that a lot of other international treaties encounter.

"But it is unjustifiable that there are still no legally binding, global provisions on the issue of violence against women," McQuigg concluded.

More on WorldViews