What Is a Woman? Dictionary, Medical, and Legal Definitions

The question “What is a woman?” seems simple enough—until you try to answer it with a single sentence. Dictionaries, doctors, courts, and cultures offer different, sometimes conflicting definitions, and the stakes are high: legal protections, access to services, and personal identity all hang on the wording.

Global female population: 49.5% (UN World Population Prospects 2022) ·
Oxford English Dictionary entries for ‘woman’: 25 distinct senses ·
Cambridge Dictionary definition updated: 2022 to include gender identity ·
Legal definition of woman in UK law: Based on biological sex under Equality Act 2010 ·
Percentage of adults who identify as women: ~99.7% cisgender (Pew Research 2021)

Four key facts capture the scope of the debate:

What defines being a woman?

Core elements: biology, identity, and social roles

• Biological sex: The American Society for Reproductive Medicine (medical professional society) describes biological sex as a multidimensional construct based on anatomy, physiology, genetics, and hormones.
• Gender identity: Arizona State University’s Embryo Project (academic resource) defines gender identity as a person’s internal sense of their own gender, distinct from gender expression.
• Social roles: The same source notes that gender refers to socially constructed roles, behaviors, and actions.

There is no single universally agreed-upon definition. Definitions often combine biological, psychological, and social factors. The implication: any single definition will inevitably exclude some experiences.

Why the question is debated

The debate centers on whether the definition should be anchored in biology or expanded to include gender identity. A 2023 SSRN article (scholarly preprint repository) argues that courts have not traditionally defined sex as only biological sex, and that gender identity is believed by scientists to have a biological basis. The catch: legal and social recognition of transgender women has moved faster than public consensus, creating friction in areas like sports, prisons, and healthcare.

What is the correct definition of woman?

Oxford English Dictionary definition

The Oxford English Dictionary defines “woman” as “an adult female human being.” This long-standing definition emphasizes biological sex. In 2023, the OED added a new sense specifically for “transgender woman,” acknowledging the term’s evolving usage.

Cambridge Dictionary definition

In 2022, the Cambridge Dictionary updated its definition to include “an adult who lives and identifies as female though they may have been said to have a different sex at birth.” This change marked a significant shift in mainstream lexicography.

Recent updates to dictionary definitions

• Cambridge Dictionary (2022): added gender identity dimension
• Oxford English Dictionary (2023): added “transgender woman” sense
• Merriam-Webster (US dictionary publisher) maintains “adult female person” but notes usage variations

The pattern: dictionary editors are responding to real-world usage, but the pace of change varies. The trade-off: updating definitions to reflect inclusivity can also be seen as erasing biological distinctions.

What is the medical definition of a woman?

Biological characteristics: chromosomes, hormones, anatomy

Medically, the term “woman” typically refers to someone with XX chromosomes, female reproductive anatomy (ovaries, fallopian tubes, uterus), and a hormonal profile dominated by estrogen and progesterone. The American Society for Reproductive Medicine states that biological sex is assigned at birth based on physical characteristics and other biological determinants.

Medical perspectives on intersex and transgender individuals

Intersex conditions—where a person’s chromosomes, hormones, or anatomy do not fit typical male or female patterns—occur in an estimated 0.05% to 1.7% of births (National Institutes of Health (US medical research agency)). This biological variation challenges any strictly binary definition. For transgender individuals, medical definitions have evolved: the World Professional Association for Transgender Health (WPATH) provides standards of care that recognize gender identity as a distinct medical reality.

How medical definitions differ from legal and social definitions

Medical definitions are rooted in observable biology, while legal definitions vary by jurisdiction, and social definitions incorporate identity and culture. A University of Chicago Journal of International Law article argues that under the CEDAW treaty, “woman” may be read to include biological, anatomical, genetic, gender performance, and/or gender identity categories. The implication: no single discipline holds the final word.

The pattern across medicine: a binary model remains the clinical default, but exceptions and legal overlaps are forcing more nuanced approaches.

What is the legal definition of a woman?

Legal definitions in the UK (Equality Act 2010)

The UK Parliament Commons Library summarizes that the Equality Act 2010 defines a woman as “female of any age.” In April 2025, the UK Supreme Court unanimously ruled that references to “man,” “woman,” and “sex” in the Act mean biological sex. However, a person with a Gender Recognition Certificate recognizing female gender is considered a woman for the purposes of the Abortion Services (Safe Access Zones) (Scotland) Act 2024, as noted by DLA Piper (global law firm).

Legal definitions in the United States (state-level variations)

A 2024 U.S. Senate bill defined “woman” as “an adult human female” and stated that “gender” should not be treated as a synonym for gender identity. Several states have enacted similar laws, while others, like California, have laws that explicitly include gender identity in definitions of sex discrimination.

International human rights frameworks

Under international human rights law, the Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) uses “woman” in a broad sense. The University of Chicago Journal of International Law argues that the term may include biological, anatomical, genetic, gender performance, and/or gender identity categories. This contrasts with the more restrictive definitions in many domestic laws.

The pattern: legal definitions are increasingly contested, with courts and legislatures in different countries moving in opposite directions. For transgender individuals, the consequence is a patchwork of recognition that can change when crossing a border.

What is the difference between woman and female?

Semantic distinctions: sex vs. gender

“Female” refers to biological sex, while “woman” can include social and cultural dimensions. The Arizona State University Embryo Project explains that biological sex commonly refers to physical characteristics, while gender refers to socially constructed roles, behaviors, and actions. Using “woman” respects gender identity when it differs from sex assigned at birth.

Usage in everyday language vs. scientific contexts

In everyday language, “female” and “woman” are often used interchangeably. In scientific contexts, “female” is the preferred term for biological sex, while “woman” is used for the social and cultural dimension. The distinction is not universally accepted; some people use the terms interchangeably.

“The UK Supreme Court has ruled that the concept of sex is binary in the Equality Act context. This means that ‘woman’ in the Act refers to biological sex, not gender identity.”

— UK Supreme Court ruling, as reported by BBC News (UK public broadcaster)

Why the choice of term matters

The choice of term can signal respect for identity or a commitment to biological definitions. For example, LGBTQ+ advocacy groups often prefer “woman” to include transgender women, while some feminist groups argue that using “female” preserves the category for those who are biologically female. The trade-off: language is never neutral, and the debate over terms reflects deeper disagreements about rights and recognition.

The implication: the difference between “woman” and “female” is not just semantic—it shapes access to resources, legal protections, and social inclusion.

Comparison of definitions

Three domains, one pattern: each definition serves a different purpose and yields different answers.

The catch: no single definition satisfies all contexts. Medical and legal definitions tend to be more rigid, while dictionary definitions are evolving to reflect usage. The practical consequence: a person may be considered a woman in one setting but not another.

Timeline: How the definition of “woman” has evolved

• Ancient–1900s: Woman defined primarily by biological sex and reproductive role
• 1960s–1970s: Second-wave feminism challenges biological determinism, emphasizes social construction
• 1990s: Transgender rights movement gains visibility, distinction between sex and gender formalized
• 2018: Wikipedia defines woman as “adult female human being” but with note on gender identity
• 2022: Cambridge Dictionary updates definition of “woman” to include gender identity
• 2023: Oxford English Dictionary adds a new sense for transgender woman
• 2025: UK Supreme Court rules that Equality Act 2010 uses biological sex (BBC News (UK public broadcaster)

The timeline signal: definitions have moved from monolithic to contested, with major inflection points in the 2020s as legal and social recognition of transgender people accelerated.

Perspectives from experts

“A person with a Gender Recognition Certificate recognizing female gender is considered a woman for the purposes of the Abortion Services (Safe Access Zones) (Scotland) Act 2024, illustrating the coexistence of legal frameworks.”

— DLA Piper analysis (global law firm)

“Clyde & Co confirmed that the UK Supreme Court ruling stated ‘woman’ in the Equality Act 2010 means a biological woman and ‘sex’ means biological sex.”

— Clyde & Co insight (international law firm)

“Clyde & Co confirmed that the UK Supreme Court ruling stated ‘woman’ in the Equality Act 2010 means a biological woman and ‘sex’ means biological sex.”

— Clyde & Co insight (international law firm)

The pattern: legal experts consistently point to the April 2025 UK Supreme Court judgment as a watershed moment, but they also note that gender recognition laws create exceptions that complicate the picture.

What does this mean for the future?

The definition of “woman” is not a settled question—it will continue to evolve through court rulings, legislative updates, and cultural shifts. The 2025 UK Supreme Court decision has clarified the legal landscape in Britain, but it also highlights the gap between legal definitions and lived experience. For transgender women, the implication is clear: legal recognition depends on jurisdiction, and the patchwork of definitions will likely persist.

Frequently asked questions