'estrogen' originates from Neo-Latin, specifically the word 'oestrogen', where 'oestr-' (from Greek 'oistros') meant 'frenzy, sexual desire' and the suffix '-gen' meant 'producer'.

'estrogen' changed from Neo-Latin 'oestrogen' (itself from Latin 'oestrus' and Greek 'oistros') and the British spelling 'oestrogen' later gave rise to the modern American spelling 'estrogen'.

Initially it meant 'that which produces estrus or sexual drive', but over time it evolved into its current meaning of 'a class of hormones that regulate female reproductive development and function'.