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

As women move through their 40s and early 50s, changes in estrogen can affect sleep, mood, focus, and emotional regulation. —Emily Cegielski, Flow Space, 9 Dec. 2025

This is because menopause causes a significant drop in estrogen – which works in regulating cholesterol and fat – increasing the risk of developing coronary heart disease or suffering a heart attack or stroke, according to the British Heart Foundation. —Sashikala Vp, CNN Money, 4 Dec. 2025

The synthetic hormones used for ovarian stimulation cause estrogen and progesterone to rise to higher levels than in the typical menstrual cycle, followed by a big drop. —Anonymous, SELF, 4 Dec. 2025

How Perimenopause Impacted My Parenting Perimenopause, the transitional period leading up to menopause, comes with hormonal changes mainly due to declining estrogen levels. —Simone Sauter, Parents, 29 Nov. 2025

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