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

Menopause can also impact tendons and ligaments, as the drop in estrogen and reduction in collagen production can weaken them. —Sara Gaynes Levy, PEOPLE, 1 Apr. 2026

Right Now Declining estrogen can cause women to lose up to 20% of their bone density in the five to seven years after menopause, and about half of all women over 50 will experience a fracture due to osteoporosis. —Allison Palmer, Kansas City Star, 1 Apr. 2026

What Happens at Work Cognitive issues linked to declining estrogen affect between 44% and 62% of women going through this transition. —Allison Palmer, Sacbee.com, 1 Apr. 2026

Hitting menopause before 45 means spending additional years with less bone-protecting estrogen in your system, which ups your risk of osteoporosis and fractures. —Erica Sloan, SELF, 31 Mar. 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