'Americanophobia' originates from Modern English, specifically from the combination of 'American' (relating to 'America') and the Greek element 'phobos', where 'American' meant 'relating to America' and 'phobos' meant 'fear'.

'Americanophobia' developed by combining the name 'America' (itself named after the Italian explorer 'Amerigo Vespucci') with the Greek-derived suffix '-phobia' (from Greek 'phobos' 'fear', via Latin and then Modern English); similar formations include 'Anglophobia' and 'xenophobia', and 'Americanophobia' follows this productive pattern in modern English coinage.

Initially it would have been used to mean simply 'fear of Americans', but over time its use has broadened in many contexts to include 'hostility or prejudice against Americans or U.S. policies' (i.e., a social or political bias rather than only a clinical fear).