'shamrock' originates from Irish, specifically the word 'seamróg', where the root 'seamair' meant 'clover' and the diminutive suffix '-óg' meant 'little'.

'shamrock' was adopted into English via Anglicization of Irish 'seamróg' (early English/Scots forms include spellings like 'shamrocke') and became established in Modern English by the 16th–17th centuries.

Initially it meant 'little clover' (a diminutive of clover), but over time it came to refer specifically to the three‑leaf clover associated with Ireland and used as a national and cultural emblem.