estrogen

American  

[es-truh-juhn] / ˈɛs trə dʒən /

noun

Biochemistry.

1. any of several major sex hormones produced primarily by the ovarian follicles of mammals, capable of inducing estrus, developing and maintaining secondary female sex characteristics, and preparing the uterus for the reception of a fertilized egg: used, especially in synthetic form, as a component of oral contraceptives, in certain cancer treatments, and in other therapies.

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estrogen British  

/ ˌɛstrəˈdʒɛnɪk, ˈɛstrədʒən, ˌiːstrə-, ˈiːstrə- /

noun

1. the usual US spelling of oestrogen

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estrogen Scientific  

/ ĕs′trə-jən /

1. Any of a group of steroid hormones that primarily regulate the growth, development, and function of the female reproductive system. The main sources of estrogen in the body are the ovaries and the placenta. Estrogen-like compounds are also formed by certain plants.

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estrogen Cultural  

1. A group of hormones, secreted mainly by the ovaries, that influence the female reproductive system in many ways, notably in preparing the body for ovulation and in the development of female secondary sex characteristics.

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Other Word Forms

• antiestrogen
  noun
• estrogenic
  adjective
• estrogenically
  adverb

Etymology

Origin of estrogen

First recorded in 1925–30; estr(us) + -o- + -gen

Explanation

Estrogen is a hormone that occurs naturally in humans and is also used in medications and treatments. Men and women both have a balance of estrogen and testosterone. People who are biologically female, with XX chromosomes, typically have a high level of estrogen and a lower level of testosterone once they reach puberty. It's the opposite in biological males. These sex hormones are responsible for the physical changes associated with the reproductive system. Estrogen is used in medications and therapeutic treatments too.

Example Sentences

The push was successful: Last fall, the FDA removed safety warnings from menopause treatments containing estrogen.

From Salon • May 13, 2026

Those with a uterus should use both estrogen and progestogen, to prevent uterine cancer.

From MarketWatch • May 12, 2026

Male obesity has been linked to low sperm count, via bifold mechanisms of increased conversion of testosterone to estrogen by adipose cells and by scrotal hyperthermia.

From Slate • Apr. 16, 2026

"Flies don't have human hormones like estrogen, suggesting that other genetic or physiological factors are driving the heightened sensitivity in females," said Biological Sciences Professor Kyung-An Han.

From Science Daily • Mar. 31, 2026

Her cheek was feathered in creases from Pet’s shoulder, and her estrogen implant was chilly in her arm.

From "Pet" by Akwaeke Emezi