Definition of estriol in US English:


(also oestriol)


  • An estrogen which is one of the metabolic products of estradiol.

    • ‘I assume that you're taking an oral dose of estriol or some combination of estriol, estrone, and estradiol.’
    • ‘Then there was balancing estradiol with progestins and, in some users, with estriol.’
    • ‘Even though the ovaries cease producing estradiol, estriol continues to be made by the adrenal glands and in fat cells.’
    • ‘The primary estrogen secreted by the ovary is estradiol, whereas that of the placenta is estriol.’
    • ‘The prominent estrogens in women are estradiol, estrone and estriol.’
    • ‘Fetal cortisol and estriol were measured in the umbilical vein plasma at delivery.’
    • ‘Natural estrogen can also easily be divided into the three types of estrogen: estradiol, estrone, and estriol.’


1930s: from oestrane (the parent molecule of most oestrogens) + tri- + -ol.