oestrogen

British

/ ˌɛstrəˈdʒɛnɪk, ˌiːstrəˈdʒɛnɪk, ˈɛstrə-, ˌiːstrə-, ˌɛstrə-, ˈiːstrədʒən /

noun

any of several steroid hormones, that are secreted chiefly by the ovaries and placenta, that induce oestrus, stimulate changes in the female reproductive organs during the oestrous cycle, and promote development of female secondary sexual characteristics

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

oestrogenic adjective
oestrogenically adverb

Etymology

Origin of oestrogen

C20: from _oestrus + _-gen

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Scans and biopsies followed, and a week and a half later she was given a diagnosis of oestrogen receptor-positive breast cancer.

From BBC • Feb. 9, 2026

The pill is an oral selective oestrogen receptor, designed to fight tumors driven by the hormone estrogen, which are estimated to account for up to 70% of all breast cancer cases.

From The Wall Street Journal • Nov. 18, 2025

HRT tops up and stabilises oestrogen levels, sometimes in combination with a synthetic or bioidentical version of progesterone.

From BBC • Nov. 6, 2025

The clinic, which has services in Birmingham and Leeds, treats people aged 16 and over, including by prescribing hormones, such as oestrogen or testosterone.

From BBC • Jun. 24, 2025

We can give you some other pills that will give your body the oestrogen it ought to be producing.

From Identity by Frikki, Aiko

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023