Dictionary.com
Thesaurus.com

oestrin

British  
/ ˈiːstrɪn, ˈɛstrɪn /

noun

  1. an obsolete term for oestrogen

"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

Etymology

Origin of oestrin

C20: from oestr ( us ) + -in