Short answers, pulled from the story.
Legal scholar Fred R. Shapiro credits Pauline M. Leet with most likely coining the term sexism on the 18th of November 1965, during a Student-Faculty Forum at Franklin and Marshall College. She defined it by comparing it to racism. The term's first appearance in print was in Caroline Bird's 1968 speech "On Being Born Female."
Sexism is prejudice or discrimination based on a person's sex or gender. It can affect anyone but primarily affects women and girls. It is linked to gender roles and stereotypes and may include the belief that one sex is intrinsically superior to another.
In 2008 the OECD found women on average had 20% less chance of holding a job and were paid 17% less than men. Eurostat found a gender pay gap of 27.5% across EU member states in 2008, and the U.S. female-to-male earnings ratio was 0.77 in 2009. When the first Equal Pay Act passed in 1963, female full-time workers earned 48.9% as much as male full-time workers.
New Zealand became the first country to grant women the vote, in 1893. French women were granted it in 1944, Greek women in 1952, Swiss women in federal elections in 1971, and women in Liechtenstein in 1984. Saudi Arabia, as of August 2015, was the most recent, extending the vote in 2011.
Sexism may have fueled the witch trials between the 15th and 18th centuries, when the misogyny of the period drove the persecution of accused women. Heinrich Kramer's Malleus Maleficarum argued that women were more likely than men to practice witchcraft. Witch-accusation killings persist today, with about 500 elderly women murdered each year in Tanzania after such accusations.
Oppositional sexism is a term coined by transfeminist author Julia Serano, who defined it as the belief that male and female are rigid, mutually exclusive categories. It normalizes masculine expression in males and feminine expression in females while demonizing the reverse, and it supports cissexism, the norm that views cisgender people as natural and privileged over transgender people.