estrogen

noun

es·​tro·​gen ˈe-strə-jən 

: any of various natural steroids (such as estradiol) that are formed from androgen precursors, that are secreted chiefly by the ovaries, placenta, adipose tissue, and testes, and that stimulate the development of female secondary sex characteristics and promote the growth and maintenance of the female reproductive system

also : any of various synthetic or semisynthetic steroids (such as ethinyl estradiol) that mimic the physiological effect of natural estrogens

Examples of estrogen in a Sentence

Recent Examples on the Web

Novel Endocrine Therapies About four out of five breast cancers are hormone-receptor positive (HR+), meaning that the hormones estrogen and/or progesterone help fuel their growth. — Petra Guglielmetti, Glamour, 6 Nov. 2026

In previous studies, scientists had found that when a receptor protein called estrogen receptor alpha was activated, the mice were more aggressive. — Mary Randolph, Scientific American, 6 Nov. 2026

The time leading up to it is called perimenopause, during which the body’s production of the hormones estrogen and progesterone declines sharply. — Laura Ungar, Los Angeles Times, 3 Nov. 2026

As estrogen levels decline around menopause, removal can outpace replacement, contributing to bone loss and osteoporosis, a condition in which bones become more fragile and porous. — Priya Bhardwaj, The Conversation, 3 Nov. 2026

Word History

Etymology

estrus + -o- + -gen

Note: The word estrogen was originally a U.S. brand name for an extract of glandular tissue used in the treatment of ovarian dysfunction. Its producer, Parke, Davis and Company, relinquished rights to the name in 1936.

First Known Use

1927, in the meaning defined above

Phrases Containing estrogen

• estrogen replacement therapy
• selective estrogen receptor modulator

Kids Definition

estrogen

noun

es·​tro·​gen ˈes-trə-jən 

: a substance that tends to cause the development of secondary sex characteristics in the female and promote the growth and normal functioning of the female reproductive system

estrogenic

ˌes-trə-ˈjen-ik

adjective

Medical Definition

estrogen

noun

es·​tro·​gen ˈes-trə-jən 

variants or chiefly British oestrogen

ˈē-strə-jən 

: any of various natural steroids (as estradiol) that are formed from androgen precursors, that are secreted chiefly by the ovaries, placenta, adipose tissue, and testes, and that stimulate the development of female secondary sex characteristics and promote the growth and maintenance of the female reproductive system

also : any of various synthetic or semisynthetic steroids (as ethinyl estradiol) that mimic the physiological effect of natural estrogens

estrogen-like adjective

or estrogenlike

-ˌlīk 

an estrogen-like compound

estrogen-like effects