A woman is an adult female human. Before adulthood, a female child or adolescent is referred to as a girl.
Anatomically the general female characteristic of human sexual dimorphism is the human female reproductive system, which includes the ovaries, fallopian tubes, uterus, vagina, and vulva. Accompanying characteristics are larger breasts, which might produce human milk, and generally a wider pelvis and broader hips. These characteristics facilitate pregnancy, childbirth and breastfeeding. Additional common characteristics are less facial and body hair, a higher body fat composition, shorter stature, and less muscle mass. Women are at greater risk of certain diseases like breast cancer, and at lower risk of other diseases like lung cancer. Genetically, women inherit typically a pair of X chromosomes, one from each parent. Sex differentiation of the female foetus is governed by the lack of a present functioning SRY gene on either one of the respective sex chromosomes.
Transgender women were assigned male at birth. Some women are intersex, meaning they have unusual sex characteristics (chromosomes, genitalia or internal sex organs), such as trisomy X or vaginal atresia.
Women are fundamental to human societies and have occupied positions at every level of society throughout history, but patriarchal gender roles have often limited or dominated women and femininity. With roles loosening during the 20th century in many societies, women have gained wider access to careers and education. Reproductive rights and women's rights have been raised globally, with some countries denying some of those rights to women. Violence against women is primarily committed by men. Many religions and governments stipulate certain rules for women. Feminist movements aim to achieve gender equality.
Etymology
The spelling of woman in English has progressed over the past millennium from "wīfmann": Bosworth & Toller, Anglo-Saxon Dictionary (Oxford, 1898–1921) p. 1219. The spelling "wifman" also occurs: C.T. Onions, Oxford Dictionary of English Etymology (Oxford, 1966) p. 1011 to wīmmann to wumman, and finally, the modern spelling woman.Webster's New World Dictionary, Second College Edition, entry for "woman". In Old English, had the gender-neutral meaning of , akin to the Modern or . The word for was or () whereas was or (from ). However, following the Norman Conquest, man began to mean , and by the late 13th century it had largely replaced .man – definition Dictionary.reference.com The consonants and in coalesced into the modern woman, while narrowed to specifically mean a married woman ().
It is a popular misconception that the term "woman" is etymologically connected to "womb". (Originally published in two volumes, 1895 and 1898, by The European Publishing Company.) "Womb" derives from the Old English word meaning (cognate to the modern German colloquial term "" from Old High German for ).
Terminology
The word woman can be used generally, to mean any female human, or specifically, to mean an adult female human as contrasted with girl. The word girl originally meant "young person of either sex" in English;Used in Middle English from c. 1300, meaning 'a child of either sex, a young person'. Its derivation is uncertain, perhaps from an Old English word which has not survived: another theory is that it developed from Old English 'gyrela', meaning 'dress, apparel': or was a diminutive form of a borrowing from another West Germanic Language. (Middle Low German has Gör, Göre, meaning 'girl or small child'.) "girl, n.". OED Online. September 2013. Oxford University Press. 13 September 2013 it was only around the beginning of the 16th century that it came to mean specifically a female child.By late 14th century a distinction was arising between female children, often called 'gay girls' – and male, or 'knave girls' -: a1375 William of Palerne (1867) l. 816 ' Whan þe gaye gerles were in-to þe gardin come, Faire floures þei founde.' ('When the gay girls came into the garden, Fair flowers they found.') By the 16th century, the unsupported word had begun to mean specifically a female: 1546 J. Heywood Dialogue Prouerbes Eng. Tongue i. x. sig. D, 'The boy thy husbande, and thou the gyrle his wyfe.' The usage meaning 'child of either sex' survived much longer in Irish English. "girl, n.". OED Online. September 2013. Oxford University Press. 13 September 2013 The term girl is sometimes used colloquially to refer to a young or unmarried woman; however, during the early 1970s, feminists challenged such use because the use of the word to refer to a fully grown woman may cause offence. In particular, previously common terms such as office girl are no longer widely used. Conversely, in certain cultures which link family honour with female virginity, the word girl (or its equivalent in other languages) is still used to refer to a never-married woman; in this sense it is used in a fashion roughly analogous to the more-or-less obsolete English maid or maiden.
The social sciences' views on what it means to be a woman have changed significantly since the early 20th century as women gained more rights and greater representation in the workforce, with scholarship in the 1970s moving toward a focus on the sex–gender distinction and social construction of gender.
Different countries have different laws, but age 18 is frequently considered the age of majority (the age at which a person is legally considered an adult). Menarche, the onset of menstruation, occurs on average at age 12–13. Many cultures have rites of passage to symbolise a girl's coming of age, such as bat mitzvah in Judaism, or a custom of a special celebration for a certain birthday (generally between 12 and 21), like the quinceañera of Latin America.
Alternative spellings of woman, such as womyn and wimmin, have been used in feminist contexts, especially since the 1970s.
Biology
Genetic characteristics
Typically, the cells of female humans contain two X chromosomes, while the cells of male humans have an X and a Y chromosome. During early foetal development, all embryos have phenotypically female genitalia up until week 6 or 7, when a male embryo's gonads differentiate into testes due to the action of the SRY gene on the Y chromosome. Sex differentiation proceeds in female humans in a way that is independent of gonadal hormones. Because humans inherit mitochondrial DNA only from the mother's ovum, genealogical researchers can trace maternal lineage far back in time.
Puberty, menstruation and menopause
Female puberty triggers many bodily changes. In response to chemical signals from the pituitary gland, the ovaries secrete hormones that stimulate maturation of the body, including increased height and weight, body hair growth, breast development and menarche (the onset of menstruation). Most girls go through menarche between ages 12–13.
Menstruation is a monthly hormonal cycle that involves the shedding of the lining of the uterus. Blood and tissue exit through the vagina. Menstrual cycles may be irregular at first, and usually become more regular by a woman's 20s. Most women are able to perform all their daily activities during menstruation, though some women experience symptoms ranging from uncomfortable to disabling or are prohibited from regular activity by strong social stigma.
The changes of puberty typically enable sexual reproduction. Pregnancy generally requires fertilisation of a woman's egg cells with a man's sperm cells. Humans are similar to other large mammals in that they usually give birth to a single offspring per pregnancy, but are unusual in being altricial, meaning young are undeveloped at time of birth and require the aid of their parents or guardians to fully mature. Sometimes humans have multiple births, most commonly twins.
Usually between ages 49–52, a woman reaches menopause, the time when menstrual periods stop permanently, and they are no longer able to bear children. Symptoms of menopause include hot flashes, night sweats, headaches, and more; both lifestyle changes and medications can help to mitigate these symptoms.
Morphological and physiological characteristics
In terms of biology, the female sex organs are involved in the reproductive system, whereas the secondary sex characteristics are involved in breastfeeding children and attracting a mate. Humans are placental mammals, which means the mother carries the foetus in the uterus and the placenta facilitates the exchange of nutrients and waste between the mother and foetus.
The internal female sex organs consist of: the ovaries, gonads that produce female gametes called ova, the fallopian tubes, tubular structures that transport the egg cells, the uterus, an organ with tissue to protect and nurture the developing foetus and its cervix to expel it, the accessory glands (Bartholin's and Skene's), two pairs of glands that help lubricate during intercourse, and the vagina, an organ used in copulating and birthing.
The vulva (external female genitalia) consists of the clitoris, labia majora, labia minora and vestibule. The vestibule is where the vaginal and urethral openings are located.
The mammary glands are hypothesised to have evolved from apocrine-like glands to produce milk, a nutritious secretion that is the most distinctive characteristic of mammals, along with live birth. In mature women, the breast is generally more prominent than in most other mammals; this prominence, not necessary for milk production, is thought to be at least partially the result of sexual selection.
Oestrogens, which are primary female sex hormones, have a significant impact on a female's body shape. They are produced in both men and women, but their levels are significantly higher in women, especially in those of reproductive age. Besides other functions, oestrogens promote the development of female secondary sexual characteristics, such as breasts and hips. As a result of oestrogens, during puberty, girls develop breasts and their hips widen. Working against oestrogen, the presence of testosterone in a pubescent female inhibits breast development and promotes muscle and facial hair development.
Circulatory system Women have lower haematocrit (the volume percentage of red blood cells in blood) than men; this is due to lower testosterone, which stimulates the production of erythropoietin by the kidney. The normal haematocrit level for a woman is 36% to 48% (for men, 41% to 50%). The normal level of haemoglobin (an oxygen-transport protein found in red blood cells) for women is 12.0 to 15.5 g/dL (for men, 13.5 to 17.5 g/dL).
Women's hearts have finer-grained textures in the muscle compared to men's hearts, and the heart muscle's overall shape and surface area also differs to men's when controlling for body size and age. In addition, women's hearts age more slowly compared to men's hearts.
Sex distribution
Girls are born slightly less frequently than boys (the ratio is around 1:1.05). Out of the total human population in 2015, there were 1018 men for every 1000 women. Historically, male children tended to be preferred over female children, which led to exposure being commonplace. Female infanticide is less acceptable in contemporary times but still occurs.
Intersex women
Intersex women have an intersex condition, usually defined as those born with ambiguous genitalia, atypical chromosomes, or atypical gonads. Most individuals with ambiguous genitalia are assigned female at birth, and most intersex women are cisgender. The medical practices to assign binary female to intersex youth is often controversial.
Some intersex conditions are associated with typical rates of female gender identity, while others are associated with substantially higher rates of gender transition compared to the general population.