Women (singular: woman) are human beings of the female gender. Women are identified by secondary sexual characteristics such as a smaller stature, the presense of breasts, smaller muscle mass, less body hair, and diminutive skeletal structure. Being female, the primary sexual characteristic of a woman is a birth canal.
Many men admit that they don't know much about women outside of this.
One can make the case that a difference in physiology between men and women can influence their personalities and preferences. Generally speaking, women are more social than men. Women are also generally seen as being more patient, gentle, nurturing, and encouraging. There are apparent differences in the reasoning behind the decisions women make, and while women prefer manly characteristics of their mates, qualities of manliness are generally not required of women.
In most societies, women are associated with certain styles that express their gender identities, such as long hair, specific clothing (such as dresses and skirts), jewelry, and body fragrances specific to women, among other things. Feminine style is typically associated with hearts and the color pink.
It should stand to reason that if men didn't know a few things about women, none of us would be here today.
For a very long time, women weren't considered to be equal with men. In fact, throughout most of the world and throughout history, a girl was considered to be the property of her father, until she was married, at which point she was considered to be the property of her spouse. This would remain the case until modern times, in which women's rights movements have swept the western world, and this trend continues to spread throughout the world. However, there remains places in the world where a woman's testimony in a court of law is considered to be of less value than the testimony of a man.
There are numerous women who insist on making men apologize for the treatment of women throughout history. Nearly all such women belong to a no-longer-progressive movement referred to as "feminism".
In the modern world, women have educational and career opportunities, can contribute to society, and be independant on much the same level as men. The modern age has seen women offered the same opportunities as men, and some have taken up leadership positions that have been seen as traditionally men's jobs (such as careers in politics). Even so, many women elect to play a housewive's role in a traditional family. A contributing factor to the prevalence of this choice is apparently a product of biological function and sexual identity; women generally aren't as career-oriented as men, and their reproductive function as childbearers gives them an inclination to be more home-oriented.